CN116924875A

CN116924875A - Method for purifying polymerization grade 1-heptene from Fischer-Tropsch oil product

Info

Publication number: CN116924875A
Application number: CN202310935070.5A
Authority: CN
Inventors: 石永杰; 沈永斌; 陈久洲; 黄浩; 邵光涛; 杨自玲; 袁华; 庄壮; 石好亮; 杨顺; 金梦; 董国如
Original assignee: National Energy Group Ningxia Coal Industry Co Ltd Coal Chemistry Industrial Technology Research Institute; National Energy Group Ningxia Coal Industry Co Ltd
Current assignee: National Energy Group Ningxia Coal Industry Co Ltd Coal Chemistry Industrial Technology Research Institute; National Energy Group Ningxia Coal Industry Co Ltd
Priority date: 2023-07-27
Filing date: 2023-07-27
Publication date: 2023-10-24

Abstract

The application provides a method for purifying polymerization grade 1-heptene from Fischer-Tropsch oil products, which comprises the following steps: s1, cutting a Fischer-Tropsch oil product to obtain a C7 fraction; s2, deacidifying the C7 fraction section, and then washing with water to obtain deacidified materials; s3, carrying out first deoxidation treatment on the deacidified material to obtain a deoxidized material; s4, carrying out complexation reaction on the deoxidized material and a complexing agent to obtain a complex, and sequentially carrying out sedimentation filtration and decomplexing on the complex to obtain a C7 normal hydrocarbon material; s5, rectifying the C7 normal hydrocarbon material to obtain a 1-heptene crude product; s6, carrying out secondary deoxidation treatment on the 1-heptene crude product to obtain the polymerization grade 1-heptene. The application can solve the problems that the research on separating 1-heptene from Fischer-Tropsch synthetic oil products is insufficient and the recovery of high-purity 1-heptene with low cost is difficult to realize in the prior art.

Description

Method for purifying polymerization grade 1-heptene from Fischer-Tropsch oil product

Technical Field

The application relates to the technical fields of coal chemical industry and fine chemical industry, in particular to a method for purifying polymer grade 1-heptene from Fischer-Tropsch oil products.

Background

Fischer-Tropsch synthesis is a core technology of a coal-to-oil process, and the main process is to convert synthesis gas into gasoline, diesel oil and other hydrocarbon products through catalytic reaction. But the product F-T crude oil is mainly used for primary chemical raw materials or fuel oil, has low economic benefit and low market competitiveness when the oil price is at a lower price for a long time. The Fischer-Tropsch synthetic oil washing naphtha is characterized by being rich in alpha-olefin (the content is more than 50%), straight-chain hydrocarbon, a small amount of naphthene, almost no aromatic hydrocarbon and the like. If the long-chain alpha-olefin in the F-T synthetic oil is separated, not only the long-chain olefin with high added value can be obtained, but also clean and high-quality aviation kerosene, lubricating oil base oil or special solvent oil and other products with higher added value can be produced, so that the capability of the coal-based F-T synthetic oil for resisting market risks is improved, and the continuous healthy development of the Fischer-Tropsch synthesis industry in China is promoted.

The consumption of the alpha-olefin with the C6 and above in China is about 19 ten thousand tons, the alpha-olefin with the C6 and above completely depends on import except that the 1-hexene has the self-yield of 4.5 ten thousand tons, and the annual demand of the alpha-olefin with the C6 and above is about 15 ten thousand tons, and the alpha-olefin is mainly used for producing AOS (C14-C16), PAO (C10, C12), lubricating oil additives and the like. At present, no experience of separating and industrialization of alpha-olefin from Fischer-Tropsch synthesis products exists in China, and only Sasol company in south Africa has the technology in the world.

Lower carbon chains such as C4 (1-butene), C6 (1-hexene) and C8 (1-octene) among the alpha-olefins are used as comonomers for the production of High Density Polyethylene (HDPE) and Linear Low Density Polyethylene (LLDPE). LAOs used in the production of HDPE and LLDPE account for more than 50% of the total consumption. At present, the conversion of comonomers in PE processes from 1-butene to higher alpha-olefins (1-hexene, 1-octene and 4-methyl-1-pentene) is generally believed to be significantly superior in tensile strength, impact strength, tear resistance and durability to long chain monomer co-resins as compared to short chain monomer co-resins, and high carbon LAOs co-monomers such as 1-hexene and 1-octene have been used in most countries around the world to replace 1-butene in the production of LLDPE resins and HDPE resins. And researches on the substitution of 1-hexene and 1-octene for odd alpha-olefins such as 1-pentene and 1-heptene as LLDPE polymerized monomers are being carried out. In addition, the 1-heptene can be used as an ideal raw material of the functional graphite nano-sheet and can also be used for producing n-octanol. The n-octanol is mainly used for producing plasticizers, stabilizers and perfume intermediates, and can also be directly used as perfume, blending flower-fragrance essence such as roses, lily and the like, and used as soap perfume.

At present, the existing research is focused on the separation and purification research of alpha-olefins with even carbon numbers, mainly 1-hexene, 1-heptene and 1-decene, the research of alpha-olefins with odd carbon numbers is almost none, the alpha-olefins in Fischer-Tropsch synthetic oil have continuous carbon numbers, and the alpha-olefins with even carbon numbers and the alpha-olefins with odd carbon numbers exist, so that the development of the separation and extraction technology of the alpha-olefins with odd carbon numbers becomes more important.

Disclosure of Invention

The application mainly aims to provide a method for purifying polymeric-grade 1-heptene from Fischer-Tropsch oil products, which aims to solve the problems that the research on separating 1-heptene from Fischer-Tropsch oil products is insufficient and the recovery of high-purity 1-heptene with low cost is difficult to realize in the prior art.

In order to achieve the above object, according to one aspect of the present application, there is provided a process for purifying polymeric 1-heptene from fischer-tropsch oils, comprising: s1, cutting a Fischer-Tropsch oil product to obtain a C7 fraction; s2, deacidifying the C7 fraction section, and then washing with water to obtain deacidified materials; s3, carrying out first deoxidation treatment on the deacidified material to obtain a deoxidized material; s4, carrying out complexation reaction on the deoxidized material and a complexing agent to obtain a complex, and sequentially carrying out sedimentation filtration and decomplexing on the complex to obtain a C7 normal hydrocarbon material; s5, rectifying the C7 normal hydrocarbon material to obtain a 1-heptene crude product; s6, carrying out secondary deoxidation treatment on the 1-heptene crude product to obtain the polymerization grade 1-heptene.

Further, the deacidification treatment includes: mixing the C7 fraction with alkali liquor, and deacidifying; preferably, the mass concentration of the alkali liquor is 3-10%; more preferably, the lye is an aqueous solution of one or more of potassium hydroxide, sodium carbonate, potassium carbonate.

Further, performing a first deoxidation treatment by using an extractant; preferably, the extractant is one or more of 1, 2-propanediol, dimethyl sulfoxide, 1, 4-butanediol, ethanolamine, 1-methyl-2-pyrrolidone; preferably, the extractant is 1, 2-propanediol; preferably, the weight ratio of the extractant to the deacidified material is (1-6): 1; preferably, the weight ratio of the extractant to the deacidified material is 2:1; preferably, the first deoxidation treatment is performed in an extraction deoxidation tower, the theoretical plate number of the extraction deoxidation tower is 20-100, and the reflux ratio is 1-20; preferably, the operating pressure of the deoxidizing column is normal pressure; preferably, the oxygenate content in the deoxygenated material after the first deoxygenation treatment is below 1000ppm.

Further, the complexing agent includes urea and an activator; wherein the activating agent is one or more of methanol, ethanol, isopropanol and acetone; more preferably, the activator is one of methanol and ethanol; preferably, the complexing agent further comprises a solvent; more preferably, the solvent is water; more preferably, the weight of solvent is no more than 6 times the weight of deoxygenated material; preferably, the weight ratio of complexing agent to C7 fraction is (2-15): 1, a step of; the temperature of the complexation reaction is between 10 ℃ below zero and 40 ℃ and the time is between 0.5 and 4 hours; preferably, the temperature of the complexation reaction is 0-20 ℃ and the time is 1-3 h; preferably, the weight ratio of the activator to the deoxidizing material is (1-6): 1, a step of; preferably, the decomplexing method comprises: mixing the complex with water, and performing heat treatment to obtain a C7 normal hydrocarbon material; preferably, the temperature of the heat treatment is 0-40 ℃ and the time is 0.5-3 h; preferably, the temperature of the heat treatment is 20-30 ℃ and the time is 1-2 h; preferably, the weight ratio of water to complexing is (0.1-10): 1.

further, the rectification treatment is carried out in a rectification tower, wherein the theoretical plate number of the rectification tower is 70-90, and the reflux ratio is 15-25; preferably, the theoretical plate number of the rectifying column is 80 and the reflux ratio is 20.

Further, performing a second deoxidization treatment with an adsorbent; preferably, the second deoxidation treatment is performed in an adsorption deoxidation tower; preferably, the adsorbent is a molecular sieve; more preferably, the molecular sieve is one or more of a 4A molecular sieve, a 5A molecular sieve, a ZSM-5 molecular sieve, a ZSM-11 molecular sieve, a ZSM-34 molecular sieve, a 13X molecular sieve, a Y-type molecular sieve, and an MCM-22 molecular sieve; preferably, after the second deoxygenation treatment, an oxygenate content of less than 5ppm in the polymeric grade 1-heptene is obtained.

Further, the method for cutting the Fischer-Tropsch oil product comprises the steps of sequentially performing primary cutting and secondary cutting; wherein, the C7+ fraction section is obtained after primary cutting, and the C7 fraction section is obtained after secondary cutting of the C7+ fraction section; preferably, the primary cutting is carried out in a first cutting tower, the theoretical plate number of the first cutting tower is 25-50, the reflux ratio is 1-20, the tower kettle temperature is 105-120 ℃, and the feeding position is in the middle part of the first cutting tower; preferably, the secondary cutting is carried out in a second cutting tower, the theoretical plate number of the second cutting tower is 25-50, the reflux ratio is 1-20, the tower kettle temperature is 120-140 ℃, and the feeding position is in the middle of the second cutting tower.

Further, in the C7 fraction, the weight percentage of the oxygen-containing compound is 0.01 to 5 percent; wherein the oxygen-containing compound comprises at least one of 1-amyl alcohol, 2-amyl ketone, 3-amyl ketone, 2-methyl-1-butanol, 3-methyl-1-butanol, valeric acid and n-propyl acetate.

Further, in the C7 fraction, the weight percentage of acidic substances is 0.01 to 0.5 percent; wherein the acidic material comprises at least one of propionic acid, butyric acid, isobutyric acid, valeric acid and malonic acid.

Further, after the second deoxygenation treatment, the method further comprises: the recovered adsorbent is recycled for use in the second deoxygenation process.

By applying the technical scheme of the application, the method for purifying the polymer grade 1-heptene from the Fischer-Tropsch oil product with complex components is provided with low cost and simple process. In the process flow of the application, firstly, deacidifying the C7 fraction section obtained by cutting, and then, carrying out first deoxidation treatment to respectively remove acidic substances and most of oxygen-containing compounds contained in the C7 fraction section; and secondly, the application removes the isoolefin by utilizing the complexation reaction, and then separates the 1-heptene and the n-heptane by rectification treatment, thereby reducing the overall energy consumption. The application carries out the second deoxidization treatment on the 1-heptene crude product obtained after rectification, and further removes the oxygen-containing compound in the product, so that the finally obtained 1-heptene product meets the requirements of polymer grade products.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

fig. 1 shows a schematic flow chart of the method according to the application.

Description of the reference numerals

A. A first cutting tower; B. a second cutting tower; C. an acidic material remover; D. deacidifying and washing tower; E. an extraction deoxidizing tower; F. an extractant recovery column; G. a deoxidizing water washing tower; H. a mixer; I. a complexing reactor; J. settling a washing tower; K. a decomplexing separator; l, rectifying tower; m, a first adsorption deoxidizing tower; n, a second adsorption deoxidizing tower; o, a dehydration tower; the method comprises the steps of,

1. Fischer-Tropsch oil products; 2. c6-distillation section; 3. c7+ fraction; 4. c8+ fraction; 5. c7, a distillation section; 6. alkali liquor; 7. discarding alkali liquor; 8. deacidifying materials before water washing; 9. waste liquid; 10. deacidifying materials after water washing; 11. an extractant and an oxygenate; 12. deoxidizing materials; 13. recovering the extractant; 14. an oxygen-containing compound; 15. a deoxidized material after washing; 16. waste liquid; 17. the deoxidized material and the complexing agent after mixing; 18. a complex; 19. partially back complexing the reactor complex; 20. a washing liquid; 21. a complex after sedimentation; 22. an aqueous complexing agent solution; 23. c7 normal hydrocarbon feed; 24. a 1-heptene post component; 25. crude 1-heptene; 26. polymerization grade 1-heptene; 27. a washing liquid; 28. complexing agent after dehydration; 29. and (3) water.

Detailed Description

It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.

In the present application, the term "polymerization grade 1-heptene" means: the acid value is less than 0.05mgKOH/g, the purity is more than or equal to 98 percent, and the oxide is less than or equal to 5PPM of 1-heptene.

To solve the problems as described above, according to an aspect of the present application, there is provided a process for purifying polymeric 1-heptene from Fischer-Tropsch oil, comprising: s1, cutting a Fischer-Tropsch oil product to obtain a C7 fraction; s2, deacidifying the C7 fraction section, and then washing with water to obtain deacidified materials; s3, carrying out first deoxidation treatment on the deacidified material to obtain a deoxidized material; s4, carrying out complexation reaction on the deoxidized material and a complexing agent to obtain a complex, and sequentially carrying out sedimentation filtration and decomplexing on the complex to obtain a C7 normal hydrocarbon material; s5, rectifying the C7 normal hydrocarbon material to obtain a 1-heptene crude product; s6, carrying out secondary deoxidation treatment on the 1-heptene crude product to obtain the polymerization grade 1-heptene.

In the application, deacidification, first deoxidation, complexation-decomplexing, rectification and second deoxidation are sequentially carried out, and the working procedures of the method lead to the reduction of the energy consumption of the whole process flow and the improvement of the purity of the obtained 1-heptene product. The deacidification process is arranged before deoxidation, so that the material requirement and equipment investment of equipment in the subsequent deacidification section can be reduced, and the rectification process is arranged after complexation, so that the tower plates can be effectively reduced, and the energy consumption is reduced.

A typical process flow diagram according to the present application is shown in fig. 1.

In a preferred embodiment, the deacidification treatment comprises: mixing the C7 fraction with alkali liquor, and deacidifying; preferably, the mass concentration of the alkali liquor is 3-10%; more preferably, the lye is an aqueous solution of one or more of potassium hydroxide, sodium carbonate, potassium carbonate. The deacidification treatment is preferably performed under the above conditions, and most of the acidic substances in the C7 cut can be removed. The residues of the lye introduced in the deacidification treatment can be removed by a subsequent water washing.

In actual operation, the water wash is preferably performed in a deacidification water wash column.

In actual operation, deacidification treatment can be carried out in a tower-type acid substance remover, and waste alkali liquid is extracted from the bottom of the tower; most of the waste lye is recycled, and a small part is extracted to better maintain the concentration of the lye.

In a preferred embodiment, the first deoxygenation treatment is performed with an extractant; preferably, the extractant is one or more of 1, 2-propanediol, dimethyl sulfoxide, 1, 4-butanediol, ethanolamine, 1-methyl-2-pyrrolidone; preferably, the extractant is 1, 2-propanediol; preferably, the weight ratio of the extractant to the deacidified material is (1-6): 1; preferably, the weight ratio of the extractant to the deacidified material is 2:1; preferably, the first deoxidation treatment is performed in an extraction deoxidation tower, the theoretical plate number of the extraction deoxidation tower is 20-100, and the reflux ratio is 1-20; preferably, the operating pressure of the deoxidizing column is normal pressure; preferably, the oxygenate content in the deoxygenated material after the first deoxygenation treatment is below 1000ppm.

The first deoxidization treatment is carried out according to the preferable conditions and parameters, which is more beneficial to the preliminary removal of the oxygen-containing compound, and the oxygen content in deoxidized materials is reduced after the first deoxidization treatment, which is more beneficial to the simplification of the subsequent process.

In the extractant, the 1, 2-propanediol is miscible with water, ethanol, diethyl ether, chloroform, acetone and other organic solvents. The catalyst has low solubility to hydrocarbons, chlorinated hydrocarbons and grease, higher boiling point, less oil phase loss and low regeneration relative energy consumption, and is more suitable for being used as an extraction deoxidizing reagent after deacidification of a C7 fraction section.

In actual operation, the extractant and the oxygen-containing compound are obtained at the bottom of the extraction and deoxidation tower, and the extractant is preferably sent to an extractant recovery tower for recovery, and the recovered extractant can be returned to the extraction and deoxidation tower for recycling.

In actual practice, to further increase the purity of the product, the method of the application further comprises, after the extractive deoxygenation treatment: and (3) delivering the deoxidized material into a deoxidized water washing tower, carrying out water washing treatment, and extracting C7 components after water washing from the top of the tower to obtain waste residues at the bottom of the tower.

In actual practice, it is preferable that a deoxidizing water scrubber is further provided after the extraction deoxidizing column to more sufficiently remove the extractant.

For better removal of isoolefins, in a preferred embodiment, the complexing agent comprises urea and an activator; wherein the activating agent is one or more of methanol, ethanol, isopropanol and acetone; preferably, the activator is one of methanol and ethanol; preferably, the complexing agent further comprises a solvent; more preferably the solvent is water; more preferably, the weight of solvent is no more than 6 times the weight of deoxygenated material; preferably, the temperature of the complexation reaction is between-10 and 40 ℃ and the time is between 0.5 and 4 hours; preferably, the temperature of the complexation reaction is 0-20 ℃ and the time is 1-3 h; preferably, the weight ratio of the complexing agent to the deoxidizing material is (2-20): 1, a step of; preferably, the weight ratio of the activator to the deoxidizing material is (1-6): 1, a step of; preferably, the decomplexing method comprises: mixing the complex with water, and performing heat treatment to obtain a C7 normal hydrocarbon material; preferably, the temperature of the heat treatment is 0-40 ℃ and the time is 0.5-3 h; preferably, the temperature of the heat treatment is 20-30 ℃ and the time is 1-2 h; preferably, the weight ratio of water to complexing is (0.1-10): 1. the above preferred complexing conditions are more advantageous for improving the separation efficiency of 1-heptene and isoolefin, and have better selectivity for C7 normal hydrocarbon and isohydrocarbon.

In actual practice, a portion of the complex product from the complexation may be returned to the complexation reactor to further facilitate the full occurrence of the complexation.

In practice, the deoxygenated material and complexing agent are preferably mixed in a mixer prior to the complexation reaction to facilitate reducing the time of the complexation reaction.

In order to better improve the purity of the 1-heptene, in a preferred embodiment, the rectification treatment is carried out in a rectification column, wherein the theoretical plate number of the rectification column is 70-90, and the reflux ratio is 15-25; preferably, the theoretical plate number of the rectifying column is 80 and the reflux ratio is 20. Because the preposed deacidification and the first deoxidation treatment process in the application have better removed the main impurities in the C7 distillation section, the requirements on the rectification process are correspondingly reduced during the rectification treatment. The purification of the polymerization grade 1-heptene can be well realized under the rectification condition, and the energy consumption is reduced.

In a preferred embodiment, the second deoxygenation treatment is performed with an adsorbent; preferably, the second deoxidation treatment is performed in an adsorption deoxidation tower; preferably, the adsorbent is a molecular sieve; more preferably, the molecular sieve is one or more of a 4A molecular sieve, a 5A molecular sieve, a ZSM-5 molecular sieve, a ZSM-11 molecular sieve, a ZSM-34 molecular sieve, a 13X molecular sieve, a Y-type molecular sieve, and an MCM-22 molecular sieve; preferably, after the second deoxygenation treatment, an oxygenate content of less than 5ppm in the polymeric grade 1-heptene is obtained. Preferably, the conditions of the second deoxidation treatment are more favorable for reducing the content of the oxygen-containing compound in the final polymerization grade 1-heptene product and improving the purity of the 1-heptene.

In order to obtain better C7 cut, in a preferred embodiment, the method for cutting Fischer-Tropsch oil comprises a first cut and a second cut performed sequentially; wherein, the C7+ fraction section is obtained after primary cutting, and the C7 fraction section is obtained after secondary cutting of the C7+ fraction section; preferably, the primary cutting is carried out in a first cutting tower, the theoretical plate number of the first cutting tower is 25-50, the reflux ratio is 1-20, the tower kettle temperature is 105-120 ℃, and the feeding position is in the middle part of the first cutting tower; preferably, the secondary cutting is carried out in a second cutting tower, the theoretical plate number of the second cutting tower is 25-50, the reflux ratio is 1-20, the tower kettle temperature is 120-140 ℃, and the feeding position is in the middle of the second cutting tower. In the above description, "middle" refers to the middle position of the tray. The cutting is carried out according to the conditions, which is more beneficial to the subsequent purification process.

In a preferred embodiment, the content of oxygenates in the C7 cut is 0.01 to 5% by weight; wherein the oxygen-containing compound comprises at least one of 1-amyl alcohol, 2-amyl ketone, 3-amyl ketone, 2-methyl-1-butanol, 3-methyl-1-butanol, valeric acid and n-propyl acetate.

In a preferred embodiment, the content of acidic substances in the C7 fraction stage is 0.01-0.5% by weight; wherein the acidic material comprises at least one of propionic acid, butyric acid, isobutyric acid, valeric acid and malonic acid.

In a preferred embodiment, after the second deoxygenation treatment, the method further comprises: the recovered adsorbent is recycled for use in the second deoxygenation process. By recovering the adsorbent, cost can be better saved. In the application, the oxygen-containing compound content in the material is lower during adsorption deoxidation, so that the recycling of the adsorbent is more facilitated.

In actual operation, the second deoxidizing treatment may be performed by using two desorption oxygen towers (first adsorption deoxidizing tower and second adsorption deoxidizing tower) at the same time. When one of the adsorbents is in a regenerated state, the other adsorbent can be used, the content of oxides in the oil phase before the adsorption and deoxidation tower is low, and one adsorbent can meet the deoxidation requirement.

In a typical embodiment of the application, as shown in FIG. 1, fischer-Tropsch oil 1 is cut for the first time in a first cutting tower A, a C6-fraction 2 is obtained at the top of the tower, and a C7+ fraction 3 is obtained at the bottom of the tower; the C7+ fraction section 3 enters a second cutting tower B for second cutting, a C8+ fraction section 4 is obtained at the bottom of the tower, and a C7 fraction section 5 is obtained at the bottom of the tower; the C7 fraction section 5 enters an acidic material remover C and is deacidified under the action of alkali liquor 6 to obtain waste alkali liquor 7 at the bottom of the tower and deacidified material 8 before water washing at the top of the tower; the deacidified material 8 before water washing enters a deacidification water washing tower D for deacidification water washing treatment to obtain waste liquid 9 at the bottom of the tower and a deacidified material 10 after water washing at the top of the tower; continuously feeding the deacidified material 10 after water washing into an extraction deoxidization tower E for extraction deoxidization treatment, obtaining an extractant and an oxygen-containing compound 11 at the bottom of the tower, and obtaining a deoxidized material 12 at the top of the tower; the deoxidized material 12 enters a deoxidized water washing tower G for deoxidized water washing treatment, waste liquid 16 is obtained at the bottom of the tower, and a deoxidized material 15 after water washing is obtained at the top of the tower; the extractant and the oxygen-containing compound 11 enter an extractant recovery tower F for extractant recovery, the recovered extractant 13 is obtained at the bottom of the tower and then returns to an extraction deoxidizing tower E, and the oxygen-containing compound 14 is obtained at the top of the tower; the deoxidized material 15 after washing and the returned dehydrated complexing agent 28 enter a mixer H to be mixed to form a mixed deoxidized material and complexing agent 17, and enter a complexing reactor I to be subjected to complexing treatment to obtain a complex 18; a part of the material in the complex 18 (as part of the complex-returning reactor complex 19) returns to the complex reactor I for complexing again; part of the residual complex 18 enters a sedimentation washing tower J for sedimentation washing treatment under the action of a washing liquid 27, so that a washing liquid 20 is obtained at the top of the tower, and a complex 21 after sedimentation is obtained at the bottom of the tower; the complex 21 and the water 29 after sedimentation enter a decomplexing separator K for decomplexing treatment, the obtained C7 normal hydrocarbon material 23 enters a rectifying tower L for rectifying treatment, the obtained complexing agent aqueous solution 22 enters a dehydrating tower O for dehydrating treatment, and the obtained dehydrated complexing agent 28 returns to a mixer H; the bottom of the rectifying tower L is provided with a 1-heptene rear component 24, and the top of the rectifying tower L is provided with a 1-heptene crude product 25; wherein the 1-heptene crude product 25 enters a first adsorption and deoxidation tower M and/or a second adsorption and deoxidation tower N for adsorption and deoxidation treatment to obtain the polymer grade 1-heptene 26.

The application is described in further detail below in connection with specific examples which are not to be construed as limiting the scope of the application as claimed.

In the following examples or comparative examples, the composition and content of the raw Fischer-Tropsch synthesis oil wash naphtha stream are shown in Table 1, unless otherwise specified.

TABLE 1

Composition of raw materials	Content (wt%)
		C4	1.77
C5	9.61
		C6	16.67
C7	24.50
		C8	24.66
C9	15.41
		C10	5.45
C11	1.64
		C12	0.29
Totals to	100 (wherein oxide 1.41%)

Example 1

Feeding Fischer-Tropsch synthesis oil-washed naphtha into a No. 1 cutting tower with a theoretical plate number of 40, wherein the reflux ratio is 4, the feeding position is the 20 th plate (from top to bottom, the same applies below), and C7+ (including C7) distillation sections are obtained from the bottom of the first cutting tower;

allowing the C7 fraction to enter a second cutting tower with theoretical plate number of 40, reflux ratio of 4 and feeding position of 20 plates, and obtaining C7 fraction from the tower top, wherein the purity reaches 99% and the yield reaches 98.5%;

feeding the C7 fraction into an organic acid remover, mixing with 3wt% NaOH solution for deacidification, feeding the deacidification product into a deacidification water washing tower after deacidification, and obtaining a washed deacidification material at the top of the tower;

the deacidification material enters an extraction deoxidization tower with the theoretical plate number of 60, 1, 2-propylene glycol is used as an extractant, the solvent ratio is 3, the reflux ratio is 2, the feeding position of the deacidification material is 40 th plate, the feeding position of the extractant is 3 rd plate, the deoxidization material is extracted from the top after deoxidization is operated at normal pressure, the mixture of the extractant and the oxygen-containing compound is extracted from the bottom of the tower, the deoxidization material enters a solvent recovery tower with the theoretical plate number of 30, the reflux ratio is 2, the operation at normal pressure is carried out, the feeding position is 9 th plate, and the extractant obtained from the bottom of the solvent recovery tower is supplemented and returned to the extraction deoxidization tower for recycling;

the deoxidized material enters a deoxidized water washing tower, C7 components are extracted from the top of the tower and mixed with complexing agent (urea+ethanol+water) in a mixer and then enter a complexing reactor, wherein the weight of urea is 5 times of that of the deoxidized material, the weight of ethanol is 3 times of that of the deoxidized material, the water quantity is 2 times of that of the deoxidized material, and the complexing temperature is 30 ℃;

the complex generated after the complexing reaction enters a sedimentation washing tower, the complex reversely washed by ethanol enters a complex decomposition system, decomplexing is carried out under the condition that the temperature is 35 ℃ and the water quantity is 5 times of the weight of the complex, the obtained C7 normal hydrocarbon material enters a rectifying tower, and urea solution obtained at the bottom of the rectifying tower returns to a mixer to continuously participate in the reaction;

and C7 normal hydrocarbon enters a rectifying tower with the theoretical plate number of 80, the reflux ratio is 20, the feeding position is the 40 th plate, a 1-heptene crude product with the purity of 98.5% is obtained from the top of the tower, and then enters an adsorption deoxidizing tower with an adsorbent of 13X molecular sieve, so that a polymerization grade 1-heptene product is obtained.

The final polymer grade 1-heptene product had a purity of 98.6%, an oxygen content of 4ppm and an acid content of < 0.05mgKOH/g.

Example 2

Feeding Fischer-Tropsch synthesis oil-washed naphtha into a No. 1 cutting tower with a theoretical plate number of 30, wherein the reflux ratio is 8, the feeding position is a 15 th plate (from top to bottom, the same applies below), and C7+ (including C7) distillation sections are obtained from the bottom of the first cutting tower;

allowing the C7 fraction to enter a second cutting tower with a theoretical plate number of 30, wherein the reflux ratio is 8, the feeding position is 15 plates, and the C7 fraction can be obtained from the tower top, the purity reaches 98.5%, and the yield reaches 98%;

feeding the C7 fraction section into an organic acid remover, mixing with a 4wt% KOH solution for deacidification, feeding the deacidified material into a deacidification water washing tower after deacidification, and obtaining a washed deacidification material at the tower top;

the deacidification material enters an extraction deoxidization tower with the theoretical plate number of 70, 1, 2-propylene glycol is used as an extractant, the solvent ratio is 3, the reflux ratio is 2, the feeding position of the deacidification material is the 40 th plate, the feeding position of the extractant is the 5 th plate, the deoxidization material is extracted from the top after deoxidization is operated at normal pressure, the mixture of the extractant and the oxygen-containing compound is extracted from the bottom of the tower, the deoxidization material enters a solvent recovery tower with the theoretical plate number of 30, the reflux ratio is 2, the normal pressure operation is carried out, the feeding position is the 15 th plate, and the extractant obtained from the bottom of the solvent recovery tower is supplemented and returned to the extraction deoxidization tower for recycling;

the deoxidized material enters a deoxidized water washing tower, C7 components are extracted from the top of the tower and mixed with complexing agent (urea+methanol+water) in a mixer and then enter a complexing reactor, wherein the weight of urea is 10 times of that of the deoxidized material, the weight of methanol is 5 times of that of the deoxidized material, the water quantity is 0.5 time of that of the deoxidized material, and the complexing temperature is 25 ℃;

the complex generated after the complexing reaction enters a sedimentation washing tower, the complex reversely washed by methanol enters a complex decomposition system, the decomplexing is carried out under the condition that the temperature is 25 ℃ and the water quantity is 3 times of the weight of the complex, the obtained C7 normal hydrocarbon material enters a rectifying tower, and urea solution obtained at the bottom of the rectifying tower returns to a mixer to continuously participate in the reaction;

and C7 normal hydrocarbon enters a rectifying tower with the theoretical plate number of 90, the reflux ratio is 15, the feeding position is 45 th plate, a 1-heptene crude product with the purity of 98.1% is obtained from the top of the tower, and then enters an adsorption deoxidizing tower with an adsorbent of a Y-type molecular sieve, so that a polymerization grade 1-heptene product is obtained.

The final polymer grade 1-heptene product had a purity of 98.3%, an oxygen content of 5ppm and an acid content of < 0.05mgKOH/g.

Example 3

The difference from example 1 is that sulfolane is used as extractant. The rest of the process flows and parameters are the same.

Example 4

The difference from example 1 is that thiourea is used as a complexing agent, and the specific components and the amounts of the complexing agent are as follows: thiourea: ethanol: after water=5:3:2 and the water solution after complexation enters a decomplexing separator for liquid separation, normal hydrocarbon enters a rectifying tower, and the rest process flows and parameters are the same.

The final polymer grade 1-heptene product had a purity of 96.1%, an oxygen content of 5ppm and an acid content of < 0.05mgKOH/g.

Example 5

The difference from example 1 is that the temperature of the complexation reaction is-10 ℃. The rest of the process flows and parameters are the same.

The final polymer grade 1-heptene product had a purity of 98.4%, an oxygen content of 4ppm and an acid content of < 0.05mgKOH/g.

Example 6

The difference from example 1 is that the theoretical plate number of the rectifying column is 70 and the reflux ratio is 25. The rest of the process flows and parameters are the same.

The final polymer grade 1-heptene product had a purity of 98.5%, an oxygen content of 4ppm and an acid content of < 0.05mgKOH/g.

Example 7

The difference from example 1 is that the weight amounts of urea, ethanol and water in the complexing agent are 8 times, 6 times and 6 times of the C9 fraction respectively. The rest of the process flows and parameters are the same.

The final polymer grade 1-heptene product had a purity of 98.0%, an oxygen content of 5ppm and an acid content of < 0.05mgKOH/g.

Comparative example 1

The difference from example 1 is that the first deoxidation treatment and the second deoxidation treatment are continuously performed, and then the complexation reaction and the rectification treatment are further performed. The rest of the process flows and parameters are the same.

The purity of the finally obtained 1-heptene product is 98.6%, the oxygen content is 4ppm, and the acid content is less than 0.05mgKOH/g.

Although the process has little influence on the product result, the regeneration period of the adsorbent in the adsorption deoxidizer can be shortened, the adsorption period of the adsorbent in the normal process is 2 months, and the adsorption period of the adsorbent is shortened to 1 month according to the process of comparative example 1.

Comparative example 2

The difference from example 1 is that the second deoxidation treatment is not performed. The rest of the process flows and parameters are the same.

The purity of the finally obtained 1-heptene product is 98.5%, the oxygen content is 600ppm (the preliminary deoxidized oxide content can be reduced to below 1000 ppm), and the acid content is less than 0.05mgKOH/g.

From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

the method has the advantages of simple process flow and low energy consumption, and gradually removes the impurities in the C7 distillation section through sequential deacidification, first deoxidation, complexation-decomplexing, rectification and second deoxidation, thereby providing a method for purifying the polymer grade 1-heptene from the Fischer-Tropsch synthetic oil product.

The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A process for purifying polymeric 1-heptene from fischer-tropsch oils comprising:

s1, cutting a Fischer-Tropsch oil product to obtain a C7 fraction;

s2, deacidifying the C7 fraction section, and then washing with water to obtain deacidified materials;

s3, carrying out first deoxidation treatment on the deacidified material to obtain a deoxidized material;

s4, carrying out a complexing reaction on the deoxidized material and a complexing agent to obtain a complex, and sequentially carrying out sedimentation filtration and decomplexing on the complex to obtain a C7 normal hydrocarbon material;

s5, rectifying the C7 normal hydrocarbon material to obtain a 1-heptene crude product;

s6, carrying out second deoxidation treatment on the 1-heptene crude product to obtain the polymerization grade 1-heptene.

2. The method for purifying polymeric 1-heptene from fischer-tropsch oil according to claim 1, wherein the deacidification treatment comprises:

mixing the C7 fraction with alkali liquor, and carrying out deacidification treatment;

preferably, the mass concentration of the alkali liquor is 3-10%;

more preferably, the lye is an aqueous solution of one or more of potassium hydroxide, sodium carbonate, potassium carbonate.

3. The process for purifying polymeric 1-heptene from fischer-tropsch oils according to claim 1 or 2, wherein the first deoxygenation treatment is performed with an extractant;

preferably, the extractant is one or more of 1, 2-propanediol, dimethylsulfoxide, 1, 4-butanediol, ethanolamine, 1-methyl-2-pyrrolidone; preferably, the extractant is 1, 2-propanediol;

preferably, the weight ratio of the extractant to the deacidified material is (1-6): 1; preferably, the weight ratio of the extractant to the deacidified material is 2:1;

preferably, the first deoxidation treatment is performed in an extraction deoxidation tower, the theoretical plate number of the extraction deoxidation tower is 20-100, and the reflux ratio is 1-20; preferably, the operating pressure of the deoxidizing column is normal pressure;

preferably, after the first deoxygenation treatment, the deoxygenated material has an oxygenate content of less than 1000ppm.

4. A process for purifying polymeric grade 1-heptene from fischer-tropsch oils according to any one of claims 1 to 3, where the complexing agent comprises urea and an activator; wherein the activating agent is one or more of methanol, ethanol, isopropanol and acetone; more preferably, the activator is one of methanol and ethanol;

preferably, the complexing agent further comprises a solvent; more preferably, the solvent is water; more preferably, the weight of the solvent is no more than 6 times the weight of the deoxygenated material;

preferably, the weight ratio of the complexing agent to the C7 fraction is (2-15): 1, a step of; the temperature of the complex reaction is-10-40 ℃ and the time is 0.5-4 h; preferably, the temperature of the complexation reaction is 0-20 ℃ and the time is 1-3 h;

preferably, the weight ratio of the activator to the deoxidizing material is (1-6): 1, a step of;

preferably, the decomplexing method comprises: mixing the complex with water, and performing heat treatment to obtain a C7 normal hydrocarbon material; preferably, the temperature of the heat treatment is 0-40 ℃ and the time is 0.5-3 h; preferably, the temperature of the heat treatment is 20-30 ℃ and the time is 1-2 h; preferably, the weight ratio of the water to the complexing is (0.1-10): 1.

5. the process for purifying polymeric 1-heptene from fischer-tropsch oils according to any one of claims 1 to 4, where the rectification treatment is carried out in a rectification column having a theoretical plate number of 70 to 90 and a reflux ratio of 15 to 25;

preferably, the theoretical plate number of the rectifying column is 80, and the reflux ratio is 20.

6. The process for purifying polymeric 1-heptene from fischer-tropsch oils according to any one of claims 1 to 5, wherein the second deoxygenation treatment is performed with an adsorbent;

preferably, the second deoxygenation treatment is performed in an adsorption deoxygenation column;

preferably, the adsorbent is a molecular sieve; more preferably, the molecular sieve is one or more of a 4A molecular sieve, a 5A molecular sieve, a ZSM-5 molecular sieve, a ZSM-11 molecular sieve, a ZSM-34 molecular sieve, a 13X molecular sieve, a Y-type molecular sieve, and an MCM-22 molecular sieve;

preferably, after the second deoxygenation treatment, an oxygenate content of less than 5ppm in the polymeric grade 1-heptene is obtained.

7. The process for purifying a polymeric grade 1-heptene from a fischer-tropsch oil according to any one of claims 1 to 6, wherein the process for cutting a fischer-tropsch oil comprises a primary cut and a secondary cut performed in sequence; wherein, C7+ fraction sections are obtained after the primary cutting, and the C7 fraction sections are obtained after the secondary cutting of the C7+ fraction sections;

preferably, the primary cutting is carried out in a first cutting tower, the theoretical plate number of the first cutting tower is 25-50, the reflux ratio is 1-20, the tower kettle temperature is 105-120 ℃, and the feeding position is in the middle of the first cutting tower;

preferably, the secondary cutting is performed in a second cutting tower, the theoretical plate number of the second cutting tower is 25-50, the reflux ratio is 1-20, the tower kettle temperature is 120-140 ℃, and the feeding position is in the middle of the second cutting tower.

8. The process for purifying polymeric 1-heptene from fischer-tropsch oil according to any one of claims 1 to 7, wherein the C7 fraction has an oxygenate content of 0.01 to 5% by weight; wherein the oxygen-containing compound comprises at least one of 1-amyl alcohol, 2-amyl ketone, 3-amyl ketone, 2-methyl-1-butanol, 3-methyl-1-butanol, valeric acid and n-propyl acetate.

9. The process for purifying polymeric 1-heptene from fischer-tropsch oil according to any one of claims 1 to 8, wherein the weight percentage of acidic material in the C7 fraction is between 0.01 and 0.5%; wherein the acidic substance comprises at least one of propionic acid, butyric acid, isobutyric acid, valeric acid and malonic acid.

10. The method of purifying a polymeric grade 1-heptene from a fischer-tropsch oil according to claim 6, wherein after the second deoxygenation treatment the method further comprises: the adsorbent is recovered for recycling in the second deoxygenation process.