Green production method for preparing SAF from olefin

Abstract

The invention discloses a production method for preparing SAF from green olefin. The production method comprises the following steps: the green olefin reacts with a first separation component, a second separation component, a light component and a heavy component which are recycled under the action of a modified ionic liquid catalyst; a reaction mixture is separated through a settling tank, the modified ionic liquid catalyst is recycled, a reaction product is separated through a first high-pressure separation tank and a first low-pressure separation tank in sequence and then enters a primary separation tower, and a first separation component and a second separation component are extracted from the bottom of the first high-pressure separation tank and the top of the first low-pressure separation tank respectively; light components, middle components and heavy components are sequentially extracted from the tower top, the tower middle and the tower bottom of the primary separation tower, the middle components are subjected to hydrogenation after being washed with water, hydrogenation products are dechlorinated and sequentially pass through a second high-pressure separation tank and a second low-pressure separation tank, gas-phase products are separated through a stabilization tower, and then SAF products are obtained. According to the method, the light and heavy components are recycled, so that the final product is only the SAF product, and the yield of the SAF product is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to a green olefin to SAF production method. BACKGROUND

[0002] Sustainable aviation fuel (SAF) is a new type of aviation fuel aimed at reducing the environmental impact of traditional aviation fuel. The International Civil Aviation Organization (ICAO) passed the International Aviation Carbon Offsetting and Reduction Scheme (CORSIA) in 2016, proposing that SAF (sustainable aviation fuel) will be widely used. The International Air Transport Association (IATA) considers the development of bio-jet fuel as an important means for the aviation industry to achieve emission reduction targets. On October 4, 2021, the 77th Annual Meeting of IATA approved the resolution of achieving net zero carbon emissions in the global aviation industry by 2050. According to the milestone targets of the resolution, the global SAF usage will reach 0.18 million tons (23 billion liters, accounting for 5.2% of total fuel demand) in 2030, and 3.50 million tons (4490 billion liters, accounting for 65.0% of total fuel demand) in 2050. Therefore, the large-scale commercial production of SAF is imminent.

[0003] There are as many as 11 production process routes for SAF, among which FT, HEFA, ATJ, and PtL are considered to have the most development potential. HEFA technology is to process plant oils, waste oils, and other raw materials through hydrogenation, deoxygenation, isomerization, and selective cracking technologies to convert them into aviation coal; FT technology is to gasify biomass and other biological raw materials to convert them into synthesis gas, and then through Fischer-Tropsch synthesis process, the synthesis gas is converted into Fischer-Tropsch synthesis oil (long-chain alkanes or aromatic hydrocarbons), and then through hydrogenation refining and isomerization to produce aviation coal; AtJ technology is to dehydrate biomass alcohols to generate olefins, and then through oligomerization to obtain alkanes as the main product, and finally through hydro-upgrading to obtain aviation coal; PtL technology is to produce hydrogen through water electrolysis using green electricity generated by photovoltaic and wind power, and then through Fischer-Tropsch synthesis or synthesis of methanol, and then through dehydration and oligomerization to convert it into aviation coal.

[0004] Green olefin polymerization to SAF technology is to use green olefins produced by dehydration of biomass alcohol or green methanol as raw materials, and then through oligomerization to generate C8-C16 hydrocarbons, and then through hydrogenation to obtain SAF. Green olefin polymerization to SAF technology can be applied in ATJ and PTL and other SAF production technology processes, and is a key step for green alcohol to SAF.

[0005] Green olefins are produced from biomass alcohol or green methanol dehydration, and the main components are ethylene, propylene and butene. At present, the olefin oligomerization technology is the SPAC process of the United States (UOP Company), the MOGD process of the United States (Mobil Company), and the oligomerization process of the French IFP Company. Among them, the SPAC process adopts a phosphoric acid-diatomite catalyst, the main raw material is propylene, and the product is mainly a trimerization product (C9), but the catalyst has a short service life (only 4-6 months) and is prone to mudification and cannot be regenerated; the MOGD process adopts a ZSM-5 molecular sieve-based catalyst, C2-C5 olefins can be used as raw materials, the product is mainly gasoline and kerosene components, and the product ratio can be adjusted as needed, but the kerosene component is not more than 70%, the reaction temperature is relatively high, the catalyst needs to be regenerated frequently (single-pass service life is about 30 days), and the energy consumption is high; the oligomerization process of the IFP Company includes Dimersol process and Difasol process, the Dimersol process adopts a nickel salt as the main catalyst and an alkyl aluminum as the cocatalyst, the raw material is butene, and the product is mainly dimers (C8), the Difasol process improves the Dimersol process by loading the nickel-based catalyst and the alkyl aluminum chloride cocatalyst on an ionic liquid to facilitate separation from the product, but the catalyst of the technology uses a large amount of alkyl aluminum or alkyl aluminum chloride, which is expensive and has high risk, can self-ignite upon air contact, and can explode upon contact with water, so the safety factor is low.

[0006] The products produced by the current olefin oligomerization technology are relatively light compared to SAF, and can only be added in small amounts for blending, and cannot be used in large quantities as aviation kerosene. Therefore, it is necessary to find a green olefin polymerization technology that can overcome the defects of the above-mentioned existing technology and produce a large amount of C8-C16 components. SUMMARY

[0007] In order to improve the proportion of kerosene in the green olefin polymerization process for producing SAF, the present application provides a production method for producing SAF from green olefins, which comprises the following steps:

[0008] (1) The raw material green olefins, the first separated component, the second separated component and the light component recycled from the previous step are dehydrated by a dryer to form dry olefins;

[0009] (2) The dry olefins and the heavy component recycled from the previous step are introduced into a polymerization reactor, and oligomerization is carried out under the action of a modified ionic liquid catalyst to form a reaction mixture;

[0010] (3) The reaction mixture entraining the modified ionic liquid catalyst is introduced into a settling tank for separation, the separated modified ionic liquid catalyst is discharged from the bottom of the settling tank and returned to the polymerization reactor for recycling, and the separated reaction product is discharged from the top of the settling tank and introduced into a first high-pressure separation tank;

[0011] (4) The first separated component discharged from the top of the first high-pressure separation tank is returned to the polymerization reactor to continue to participate in the reaction, and the high component discharged from the bottom of the first high-pressure separation tank is introduced into the first low-pressure separation tank;

[0012] (5) The second separated component discharged from the top of the first low-pressure separation tank is returned to the polymerization reactor to continue to participate in the reaction, and the polymerization product discharged from the bottom of the first low-pressure separation tank is introduced into the primary fractionating column;

[0013] (6) The light component is discharged from the top of the primary fractionating column and returned to the polymerization reactor to continue to participate in the reaction; the intermediate component is discharged from the middle of the primary fractionating column; and the heavy component is discharged from the bottom of the primary fractionating column and returned to the polymerization reactor to continue to participate in the reaction;

[0014] (7) The intermediate component is introduced into the hydrogenation reactor after being washed with water to perform hydrogenation reaction and form a hydrogenation product; in the hydrogenation reactor, the organic chloride in the intermediate component reacts with zinc oxide in the dechlorination agent to form zinc chloride, so that the hydrogen chloride is fixed on the dechlorination agent, and the hydrogenation product becomes a dechlorination product;

[0015] (8) The dechlorination product is introduced into the dechlorination reactor filled with the dechlorination agent, the hydrogen chloride reacts with the zinc oxide in the dechlorination agent to form zinc chloride, so that the hydrogen chloride is fixed on the dechlorination agent, and the hydrogenation product becomes a dechlorination product; the dechlorination product is subjected to high-pressure separation and low-pressure separation in the second high-pressure separation tank and the second low-pressure separation tank in sequence; the hydrogen gas separated from the top of the second high-pressure separation tank is returned to the hydrogenation reactor for recycling, and the crude hydrogen separated from the top of the second low-pressure separation tank is sent to a flare for combustion;

[0016] (9) The liquid-phase product separated from the bottom of the second low-pressure separation tank is introduced into the stabilizing column, the gas-phase product separated from the top of the stabilizing column is sent to a flare, and the product separated from the bottom of the stabilizing column is the SAF product.

[0017] The primary fractionating column is a fractionating column, the polymerization product is introduced into the middle of the primary fractionating column, the feed temperature of the primary fractionating column is 250°C, the top temperature is controlled at 150±3°C, the bottom temperature is controlled at 295-300°C, and the pressure in the column is 0.05-0.1 MPa.

[0018] The stabilizing column is a fractionating column, the liquid-phase product is introduced into the middle of the stabilizing column, the feed temperature of the stabilizing column is 210-230°C, the top temperature is controlled at 150±3°C, the bottom temperature is controlled at 220±3°C, and the pressure in the column is 0.05-0.1 MPa.

[0019] The main component of the first separated component is C2 olefin, and the main component of the second separated component is C3 and C4 olefin.

[0020] Specifically, the green olefin is formed by dehydration of biomass alcohol or green methanol, and the content of ethylene in the green olefin is 0.1-50 wt%, the content of propylene is 30-70 wt%, and the content of butene is 5-30 wt%.

[0021] The wastewater generated by the intermediate component in the water washing process enters the wastewater treatment system for harmless treatment. Specifically, the dechlorination agent in the dechlorination reactor specifically adopts a zinc oxide-based dechlorination agent, the main component of which is zinc oxide (ZnO), or zinc oxide is used in combination with other metal oxides (such as aluminum oxide, calcium oxide, copper oxide, etc.), to realize the dechlorination function through physical adsorption and chemical reaction. The reaction principle is that zinc oxide reacts irreversibly with HCl to form stable zinc chloride (ZnCl2), and the reaction formula is:

[0022] ZnO + 2HCl → ZnCl2 + H2O

[0023] At the same time, the carrier (such as activated alumina) in the dechlorination agent provides physical adsorption capacity, improving the chlorine capacity and dechlorination efficiency.

[0024] In the present application, the light components separated from the first high-pressure separation tank, the first low-pressure separation tank and the primary fractionating column, and the heavy components discharged from the bottom of the primary fractionating column are all returned to the polymerization reactor for further reaction, forming a light and heavy component full recycling process, so that more than 99% of the products are SAF, and the utilization rate of raw materials is improved. The light components returned to the polymerization reactor mainly participate in oligomerization, and the heavy components are cracked to form small molecule products and large molecule products, wherein the small molecule products continue to participate in oligomerization or combine with large molecules, and the large molecule products are part of the SAF product.

[0025] The intermediate component in the present application is only washed with water, and the alkali washing process in the ionic liquid or aluminum chloride polymerization technology is cancelled. Since the present application adopts a light and heavy component full recycling process, a small amount of modified ionic liquid catalyst dissolved in the reaction product can return to the polymerization reactor with the heavy component, thereby the alkali washing process can be cancelled, and only water washing process can be used to clean the intermediate component, reducing the amount of waste discharge and improving the environmental friendliness of production.

[0026] The oligomerization reaction in the present application adopts a modified ionic liquid catalysis process, which has high catalyst activity, mild reaction conditions, reduces energy consumption, and can avoid the problem of frequent coking of solid catalysts.

[0027] The light component discharged from the top of the primary fractionating tower is mainly C5-C7 hydrocarbon products, and the heavy component discharged from the bottom of the primary fractionating tower is mainly hydrocarbon products greater than C16. The C5-C7 hydrocarbon products continue to participate in the oligomerization reaction after being returned to the polymerization reactor. The hydrocarbon products greater than C16 are cracked and disproportionated under the action of the modified ionic liquid catalyst after being returned to the polymerization reactor to generate C8-C16 components, so that the final product is only the SAF product, and the yield of the SAF product is improved.

[0028] Specifically, in step (1), the molecular sieve is used for dehydration, and the molecular sieve is at least one of 3A, 4A, 5A or 13X. Green olefins are produced by dehydration of biomass alcohol or green methanol, and the water content is usually 50-500 PPM. Water will hydrolyze with AlCl3 in the ionic liquid to generate HCl and Al(OH)3. Therefore, too high water content is toxic to the catalyst. The above-mentioned molecular sieves all have good dehydration performance, and can remove the water in the green olefins to less than 5 ppm to prolong the service life of the catalyst.

[0029] Specifically, in step (2), the polymerization reactor is a tubular reactor, a stirred reaction kettle or a tower reactor. When the polymerization reactor is a tubular reactor, the tubular reactor is filled with a packing, the material of the packing is ceramic, corundum, quartz or inert alumina, and the shape of the packing is at least one of spherical, annular or saddle-shaped. In actual production process, the specific equipment can be selected according to the specific equipment.

[0030] Further, in step (2), during the oligomerization reaction, the reaction pressure is 2.0-6.0 MPa, the reaction temperature is 50-150℃, the mass ratio of the modified ionic liquid catalyst to the dry olefin is (2-20):100, and the reaction time is 1-30 min.

[0031] When the polymerization reactor is a tubular reactor or a stirred reaction kettle, the dry olefin and the modified ionic liquid catalyst are both fed into the polymerization reactor from the bottom of the polymerization reactor, and the reaction mixture and the modified ionic liquid catalyst are both discharged from the top of the polymerization reactor. When the polymerization reactor is a tower reactor, the dry olefin is fed into the reactor from the lower part of the tower reactor, and the modified ionic liquid catalyst is fed into the tower reactor from the upper part. After the dry olefin and the modified ionic liquid catalyst are countercurrently contacted and reacted, part of the modified ionic liquid catalyst is discharged from the bottom of the tower reactor and returned to the tower reactor through a catalyst circulating pump, and part of the modified ionic liquid catalyst is discharged from the top of the tower reactor and enters a settling tank with the reaction mixture.

[0032] Specifically, in step (2), the cation in the modified ionic liquid catalyst is at least one of imidazole cation, quaternary ammonium cation or pyridine cation, and the anion is AlCl4- / Al2Cl7 - , the modifier is TiCl n . The TiCl n Specifically, at least one of TiCl4 or TiCl3. The imidazole cation is specifically 1-ethyl-3-methylimidazole cation, 1-propyl-3-methylimidazole cation, 1-butyl-3-methylimidazole cation, 1-pentyl-3-methylimidazole cation, 1-hexyl-3-methylimidazole cation, 1-benzyl-3-methylimidazole cation, 1-ethyl acetate-3-methylimidazole cation, 1-allyl-3-methylimidazole cation or 1-2 (hydroxyethyl)-3-methylimidazole cation, the quaternary ammonium cation is specifically diethylammonium cation, trimethylammonium cation, triethylammonium cation, tri-n-propylammonium cation, tri-n-butylammonium cation, tetraethylammonium cation or tetrabutylammonium cation, the pyridine cation is specifically N-n-butylpyridine cation, N-propylpyridine cation, N-ethylpyridine cation or N-butyl-N-methylpiperidine cation.

[0033] The modified ionic liquid catalyst in the application is actually aluminum trichloride-based ionic liquid modified by TiCl n In modern chemical theory, it is generally believed that the reaction mechanism of ionic liquid catalyzed olefin oligomerization follows the carbonium ion mechanism, specifically:

[0034] The metal chloride hydrolyzes with trace amount of water in the reaction system to generate hydrogen ions, which then react with olefin molecules to generate carbonium ions, and then generate oligomerization products through chain growth, chain transfer, chain rearrangement and deprotonation. Taking metal chloride catalyzed isobutene as an example, the reaction equation is as follows:

[0035]

[0036] Another view is that the metal chloride is "self-ionized" to generate positive ions to initiate polymerization. Taking TiCl4 catalyzed isobutene polymerization as an example, the reaction principle is as follows:

[0037]

[0038] The metal chloride ionic liquid catalyst for olefin polymerization generally adopts aluminum chloride-based ionic liquid, because the acidity of aluminum chloride is higher, and the catalytic polymerization activity is higher; the high acidity of aluminum chloride makes it have strong olefin cracking function. The catalytic cracking of the acidic catalyst is also dominated by the carbocation mechanism, and the carbocation cracking mechanism is divided into bimolecular cracking and monomolecular cracking mechanism. Generally speaking, short-chain olefins mostly follow the bimolecular cracking mechanism, and long-chain olefins mainly follow the monomolecular cracking mechanism. Studies have shown that the main cracking mechanism of butene is bimolecular mechanism, pentene and hexene are both single-molecule and bimolecular cracking, and heptene and octene are mainly single-molecule cracking mechanism. Studies have shown that the essence of the bimolecular cracking mechanism of olefins is that two short-chain olefin molecules are polymerized into a long-chain olefin molecule for cracking, and the essential mechanism is the same as the monomolecular mechanism, that is, the long-chain olefin molecule forms a carbocation under the action of the acidic catalyst, and then β-fragmentation (β-cracking) occurs, thereby forming one small olefin molecule and one small carbocation.

[0039] The strength of the catalyst acidity will affect the reaction energy barrier of various reactions, and the higher the catalyst acidity, the lower the reaction energy barrier of the protonation and β-cracking of the olefin, and the more prone to polymerization and cracking reaction. However, the main component of SAF is C8-C16 component, and if aluminum chloride-based ionic liquid is directly used, a large amount of light components will be produced, and even if the light component is recycled by the process, higher energy consumption will be caused, resulting in an increase in cost. Therefore, TiCl n is added to the aluminum chloride-based ionic liquid.

[0040] Since the electronegativity of Ti is lower than that of Al, the addition of TiCl n reduces the electron-withdrawing ability of Al, thereby reducing the acidity of the catalyst. TiCl n itself has a catalytic function and also has a catalytic effect on olefin polymerization. By controlling the appropriate proportion of modification, the combined action of the two can slightly increase the polymerization reaction activity of the catalyst, and at the same time reduce the cracking performance of the catalyst, so that the C5-C7 component in the polymerization product is reduced. At the same time, Ti can form a double-chlorine bridge connection structure with Al, for example, TiCl3, and its structure is as follows:

[0041]

[0042] The structure is conducive to the increase of the olefin polymerization chain, so that the polymerization product is developed to the heavy direction.

[0043] The molar ratio of Ti element to Al element is controlled to be (0.05-0.2):1, and the anion is mainly AlCl4 - / Al2Cl7 -so that the product does not produce too many C16 components. With the polymerization catalyst, the C8-C16 component selectivity of the polymerization product reaches 85-90%, the C5-C7 component is less than 10%, and the content of components greater than C16 is less than 5%. At the same time, because the main anion of the catalyst is AlCl4 - / Al2Cl7 - , the heavy components that can be recycled are cracked, thereby avoiding the continuous extension of the molecular chain to obtain the SAF component.

[0044] Specifically, in the modified ionic liquid catalyst, the molar ratio of the cation to the anion is 1:(1.5-2.5). In this application, the anion is AlCl4 - / Al2Cl7 - , when the molar fraction of AlCl3 in the ionic liquid is <0.5, Al 3+ exists in the form of AlCl4 - , and other anions are Cl - . Relative to AlCl3, the excess Cl - is a weak base, which causes the overall ionic liquid to exhibit weak basicity. When the molar fraction of AlCl3 is 0.5, the ionic liquid exhibits neutrality. Therefore, when the molar fraction of AlCl3 is ≤0.5, the corresponding ionic liquid does not have catalytic activity. When the molar fraction of AlCl3 is >0.5, AlCl3 combines with AlCl4 - to form the anion Al2Cl7 - , which exhibits Lewis acidity. To ensure the proper catalytic function of the modified ionic liquid catalyst, the molar ratio of the cation to the anion is controlled to be 1:(1.5-2.5). When the molar ratio of the anion to the cation is less than 1.5:1, the anion Al2Cl7 - is less, the Lewis acidity is not enough, the activity of the catalyst is not high, and the conversion rate of the raw material is low; when the molar ratio is greater than 2.5:1, excess AlCl3 combines with Al2Cl7 - to form a large amount of the anion Al3Cl 10 - , the acidity is too strong, which causes too much cracking and a large amount of light components.

[0045] Specifically, in the modified ionic liquid catalyst, the molar ratio of Ti to Al is (0.05-0.2):1. Below this range, the content of the Ti-Al double chloro bridge structure is too small to modify the catalyst, the catalyst has strong acidity, and the cracking performance is high; above this range, the acidity of the catalyst is greatly reduced, the polymerization activity is reduced, the conversion rate of the raw material is reduced, and there are more Ti-Al double chloro bridge structures, the polymerization degree is deepened, and the product is heavy.

[0046] Further, the modified ionic liquid catalyst is prepared as follows: under the protection of nitrogen atmosphere, cation chloride and AlCl3 are added into a synthesis reactor, stirring is maintained, and after reaction at 70-120°C for 0.5-10h, TiCl n is further added, and the reaction is continued for 1-5h to obtain the modified ionic liquid catalyst. The cation chloride refers to the chloride of imidazole, quaternary ammonium or pyridine. If the reaction temperature is too low, the components of the catalyst do not react completely, and there are some insoluble substances, the components of the generated ionic liquid are not in the ideal ratio, and the activity cannot meet the requirements. If the reaction temperature is too high, the energy consumption is increased, and even some components (AlCl3 or TiCl4) are generated or volatilized. If the reaction time is too short, the reaction is not complete, and the catalyst activity is affected. If the reaction time is too long, the synthesis energy consumption is increased.

[0047] Further, in step (7), the hydrogenation reactor is a fixed bed reactor, and the hydrogenation catalyst is a nickel-based catalyst modified by Mo or W. In the hydrogenation catalyst, the content of nickel is 15-50wt%, and the content of Mo or W is 1-5wt%. The reaction temperature of the hydrogenation reaction is 150-280°C, the reaction pressure is 2.0-8.0MPa, the mass space velocity is 0.2-1.0h -1 , and the volume ratio of hydrogen to oil is (300-500):1. Although increasing the hydrogenation temperature is beneficial to the reaction, too high temperature will cause cracking. Too low temperature cannot decompose all the organic chlorides to completely remove the organic chlorides in the product. Increasing the reaction pressure is beneficial to the hydrogenation, and the higher the reaction pressure, the higher the hydrogen partial pressure, which is beneficial to the forward direction of the hydrogenation reaction, can effectively prevent the coking reaction of the catalyst, is beneficial to the protection of the catalyst, and improves the stability of the catalyst. However, increasing the reaction pressure requires increasing the pressure rating of the production equipment and the operating cost. Reducing the pressure is not conducive to the hydrogenation reaction, and will lead to incomplete hydrogenation. Reducing the space velocity is beneficial to the hydrogenation, and low space velocity is also beneficial to the reduction of the reaction temperature, less cracking, and better product quality. However, the demand for catalyst is larger, and the investment cost is increased. Increasing the space velocity is not conducive to the hydrogenation reaction, and will lead to incomplete hydrogenation. Increasing the hydrogen to oil ratio is beneficial to the hydrogenation reaction, and can make the raw material oil more evenly distributed in the catalyst, can avoid the hot spot of the catalyst bed, and the circulating hydrogen is the heat carrier of the reaction, which can control the bed temperature rise. However, too high hydrogen to oil ratio will increase the system pressure drop, shorten the contact time of the oil and the catalyst, and lead to the decrease of the reaction depth, increase the load of the circulating machine, and increase the power consumption. Too low hydrogen to oil ratio will easily cause insufficient hydrogenation capacity. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 is the process schematic diagram used when the modified ionic liquid catalyst activity is evaluated by one-time passing of the modified ionic liquid catalyst in a tubular reactor or a stirred reaction kettle.

[0049] Figure 2is the flow diagram used in the present application when using a tubular reactor or a stirred reactor to evaluate the activity of the modified ionic liquid catalyst for full circulation of light and heavy components.

[0050] Figure 3 is the flow diagram used in the present application when using a tower reactor to evaluate the activity of the modified ionic liquid catalyst for one-time passing.

[0051] Figure 4 is the flow diagram used in the present application when using a tower reactor to evaluate the activity of the modified ionic liquid catalyst for full circulation of light and heavy components.

[0052] Figure 5 is Figure 2 is the structural diagram when the primary separation tower is composed of two series-connected fractionating towers. DETAILED DESCRIPTION

[0053] The present application is described in more detail below through examples.

[0054] The following examples are divided into two evaluation processes, one-time passing and full circulation of light and heavy components. The one-time passing mainly evaluates the activity of the polymerization catalyst, and the full circulation of light and heavy components mainly investigates the effect of the recycling process of the present application. The top outlet of the settling tank is sampled, washed with water, and then analyzed and calculated to obtain the olefin conversion rate, light component selectivity, heavy component selectivity, and SAF component selectivity as the investigation indexes. The SAF product outlet of the stabilizing tower in the full circulation process of light and heavy components is sampled, and the chlorine content, bromine index, distillation range, and component proportion are analyzed as the investigation targets. The calculation formulas are as follows:

[0055]

[0056] The green olefin raw material of all examples is provided by the Second Institute of Civil Aviation of China, and its composition is as follows:

[0057]

[0058]

[0059] AlCl3, TiCl4, and triethylamine hydrochloride are purchased from Nanjing Chemical Reagent Co., Ltd. The modified ionic liquid catalyst is prepared as follows:

[0060] Under the protection of nitrogen atmosphere, triethylamine hydrochloride and AlCl3 were added into a three-necked flask, kept stirring, reacted at 90°C for 3h, kept the temperature unchanged, then added modifier TiCl4, and continued to react for 2h to obtain the modified ionic liquid catalyst. It can be understood that in other embodiments, triethylamine hydrochloride can be replaced by other quaternary ammonium hydrochlorides or imidazole hydrochlorides and pyridine hydrochlorides, and the modifier TiCl4 can be replaced by TiCl3. For details, please refer to the related content in the foregoing, which will not be described here.

[0061] The hydrogenation catalyst was prepared by co-precipitation method, and the preparation steps were as follows: (1) preparing an active metal aqueous solution by mixing nickel nitrate and / or ammonium heptamolybdate; (2) adding the carrier Al2O3 into the active metal aqueous solution; (3) preparing a sodium carbonate aqueous solution; (4) slowly adding the sodium carbonate aqueous solution into the active metal aqueous solution for co-precipitation under stirring, and finally controlling the pH value to 8-9 to form a slurry; (5) filtering, washing, drying, calcining and tabletting the slurry; (6) reducing the active metal under hydrogen atmosphere before use, and the reduction temperature was 220-380°C, the hydrogen agent ratio was 300-500:1, and the reduction time was 15-30h. The unexplained related process can be prepared by using the existing conventional process. It can be understood that in other embodiments, the catalyst preparation method can be to load nickel and molybdenum on Al2O3 by impregnation method.

[0062] In the following examples 1-3, the following flow was used:

[0063] The evaluation process of the catalytic activity of the modified ionic liquid catalyst was carried out in the stirring reaction kettle 32 lined with tetrafluoroethylene.

[0064] Please refer to Figure 1 The evaluation process of the catalytic activity of the modified ionic liquid catalyst was carried out in the stirring reaction kettle 32 lined with tetrafluoroethylene.

[0065] The dried olefins were heated by the refrigerant channel of the raw material heat exchanger 51, and then entered the stirring reaction kettle 32 together with the fresh modified ionic liquid catalyst 102 through the bottom to carry out oligomerization reaction. The reaction mixture entrained with the modified ionic liquid catalyst went out from the top of the stirring reaction kettle 32, and then entered the settling tank 33 after being cooled by the heating medium channel of the raw material heat exchanger 51. The separated modified ionic liquid catalyst was discharged from the bottom of the settling tank for recycling, and the separated reaction mixture 331 was discharged from the top of the settling tank 33. After detecting the components in the reaction mixture, the catalytic activity of the modified ionic liquid catalyst was evaluated. The fresh modified ionic liquid catalyst 102 was transported by the catalyst pump 12.

[0066] Please refer to Figure 2, the evaluation process for the full circulation of light and heavy components is as follows:

[0067] (1) Under the action of the raw material pump 11, the green olefins 101 as raw materials are dehydrated to a water content of <5PPm together with the first separated component, the second separated component and the light component recycled from the dryer packed with 3A molecular sieves to form dry olefins.

[0068] (2) The dry olefins are heated by the coolant channel of the raw material heat exchanger 51 and then enter the bottom of the stirred reaction kettle 32 together with the heavy component recycled and the modified ionic liquid catalyst to perform oligomerization reaction and form a reaction mixture. Fresh modified ionic liquid catalyst 102 is delivered by the catalyst pump 12.

[0069] (3) The reaction mixture entraining the modified ionic liquid catalyst is discharged from the top of the stirred reaction kettle 32 and then cooled by the heating medium channel of the raw material heat exchanger 51, and then enters the settling tank 33 for separation. The separated modified ionic liquid catalyst is discharged from the bottom of the settling tank 33 and then returned to the polymerization reactor from the bottom of the polymerization reactor under the action of the first circulation pump 13 for recycling. The separated reaction product is discharged from the top of the settling tank 33 and then enters the first high-pressure separation tank 34.

[0070] (4) The first separated component rich in C2 olefins discharged from the tank top of the first high-pressure separation tank 34 enters the first buffer tank 52 and is mixed with the second separated component described below, and then is compressed by the first compressor 21 and mixed with the green olefins and the light component described below, and then is returned to the stirred reaction kettle 32 to continue to participate in the reaction. The high component discharged from the tank bottom of the first high-pressure separation tank 34 enters the first low-pressure separation tank 35. The pressure in the first high-pressure separation tank is provided by the pressure carried by the reaction product itself.

[0071] (5) The second separated component rich in C3 and C4 olefins discharged from the tank top of the first low-pressure separation tank 35 also enters the first buffer tank and is mixed with the first separated component, and then is returned to the stirred reaction kettle by the first compressor 21 to continue to participate in the reaction. The polymerization product discharged from the tank bottom of the first low-pressure separation tank 35 enters the primary column 36. In this application, the pressure in the first low-pressure separation tank is 0.05-0.1 MPa.

[0072] The first buffer tank is used to buffer the pressure and flow of the first separated component and the second separated component, and to separate a small amount of liquid carried in the first separated component and the second component. The liquid separated in the first buffer tank is discharged from the bottom of the first buffer tank and then enters the wastewater treatment system for harmless treatment.

[0073] (6) The primary fractionating column is a fractionating column, the polymerization product enters the primary fractionating column from the middle, the feed temperature is 250°C, the overhead temperature is controlled at 150±3°C, the bottom temperature is controlled at 295-300°C, and the pressure in the column is 0.05-0.1 MPa. The light component is discharged from the overhead of the primary fractionating column 36 into the first reflux drum 361, part of the condensate in the first reflux drum 361 is returned to the primary fractionating column, and the other part is mixed with the green olefins and the first separated component and the second separated component under the action of the second circulating pump 14 to serve as raw materials, and after drying in the dryer 31, is returned to the stirred reaction kettle 32 to continue to participate in the reaction; the middle component is discharged from the middle side line 363 of the primary fractionating column into the water washing column 37; and the heavy component is discharged from the bottom of the primary fractionating column and is divided into two streams, one of which is returned to the primary fractionating column after being heated by the first reboiler 362, and the other of which is returned to the polymerization reactor under the action of the third circulating pump 15 to continue to participate in the reaction.

[0074] It can be understood that in other embodiments, the primary fractionating column can also be composed of two fractionating columns connected in series, and specific reference can be made to Figure 5 , along the direction of the material, the two fractionating columns are an upstream side fractionating column 336 and a downstream side fractionating column 337, the polymerization product enters the upstream side fractionating column from the middle, and the light component is separated from the overhead of the upstream side fractionating column, the bottom material of the upstream side fractionating column enters the downstream side fractionating column from the middle, and the middle component is collected from the overhead of the downstream side fractionating column, and the heavy component is collected from the bottom of the downstream side fractionating column.

[0075] (7) The middle component enters the water washing column 37 from the lower part and flows upward to be washed in countercurrent contact with the washing water 61 entering the water washing column from the upper part. In this application, the temperature of the water washing column is controlled in the range of 50-90°C, and the water-oil ratio is in the range of (3-5):1; and in Examples 1-3, the water washing temperature is 80°C, and the water-oil ratio is 3:1.

[0076] After being washed, the middle component is heated by the coolant channel of the second heat exchanger 53 and the heating furnace 54 in sequence and then enters the hydrogenation reactor 38 to perform hydrogenation reaction to form a hydrogenation product. New hydrogen 103 is added to the middle component after being washed by the second compressor 22.

[0077] In the hydrogenation reactor, the organic chlorides in the middle component become hydrogen chloride and alkanes. The waste water discharged from the bottom of the water washing column enters a waste water treatment system for harmless treatment.

[0078] (8) The hydrogenation product enters the dechlorination reactor 39 filled with dechlorination agent, the hydrogen chloride reacts with the zinc oxide in the dechlorination agent to produce zinc chloride, the hydrogen chloride is fixed on the dechlorination agent, and the hydrogenation product becomes a dechlorination product. The dechlorination product is cooled by the heat medium channel of the second heat exchanger, and then is subjected to high pressure separation and low pressure separation by the second high pressure separation drum 40 and the second low pressure separation drum 41 in sequence.

[0079] In this embodiment, the dechlorination agent specifically adopts zinc oxide-based dechlorination agent. The dechlorination agent in this embodiment is prepared by the following method: 30wt% zinc oxide, 30wt% calcium oxide, 20wt% aluminum oxide and 20wt% kaolin are uniformly mixed, then extruded into a 5mm diameter strip, then activated at 70°C for 9h, then activated at 350°C for 3h, and finally sieved through a 10 mesh sieve to obtain the dechlorination agent.

[0080] It can be understood that in other embodiments, commercially available zinc oxide-based dechlorination agents such as T408 type dechlorination agent of Northwest Chemical Research Institute Co., Ltd. can also be used.

[0081] The hydrogen separated from the top of the second high-pressure separation tank is buffered by the second buffer tank 55, mixed with fresh hydrogen, and returned to the hydrogenation reactor under the action of the second compressor for recycling.

[0082] The liquid discharged from the bottom of the second high-pressure separation tank enters the second low-pressure separation tank, and the crude hydrogen 111 separated from the top of the second low-pressure separation tank is burned in a flare. The pressure in the second high-pressure separation tank is provided by the dechlorination product itself. In this application, the pressure in the second low-pressure separation tank is 0.05-0.1 MPa.

[0083] (9) The liquid phase product separated from the bottom of the second low-pressure separation tank enters the middle of the stabilizing tower 42, the gas phase product 112 separated from the top of the stabilizing tower is burned in a flare, and the product separated from the bottom of the stabilizing tower is the SAF product 113. The stabilizing tower is a fractional distillation tower, the liquid phase product enters the middle of the stabilizing tower, the feed temperature is 210-230°C, the top temperature is controlled at 150±3°C, the bottom temperature is controlled at 220±3°C, and the pressure in the tower is 0.05-0.1 MPa.

[0084] A second reflux tank is provided at the top of the stabilizing tower, the product discharged from the top of the stabilizing tower first enters the second reflux tank 421, the condensate in the second reflux tank returns to the stabilizing tower, and the gas phase product 112 discharged from the top of the second reflux tank is burned in a flare. A second reboiler 422 is provided at the bottom of the stabilizing tower, the bottom material is divided into two streams after being discharged, one of which is heated by the second reboiler 422 and then returned to the stabilizing tower, and the other is the SAF product 113.

[0085] Example 1

[0086] The molar ratio of raw materials AlCl3, TiCl4, and triethylamine hydrochloride for preparing the modified ionic liquid catalyst is 2:0.2:1, the polymerization reaction conditions for one-time through and full cycle evaluation process are both 4.0 MPa of reaction pressure and 70°C of reaction temperature, and when oligomerization reaction is performed, the mass ratio of the modified ionic liquid catalyst to dry olefin is 20:100, and the reaction time is 20 min.

[0087] The pressure in the primary fractionating tower was controlled at 0.06 MPa. The feed temperature of the stabilizing tower was 220°C, and the pressure in the tower was controlled at 0.06 MPa.

[0088] In this embodiment, the pressure in the first low-pressure separation tank was 0.1 MPa, and the pressure in the second low-pressure separation tank was 0.1 MPa.

[0089] In the hydrogenation reaction, the hydrogenation catalyst was a Mo-modified nickel catalyst. The content of nickel in the hydrogenation catalyst was 35 wt%, and the content of Mo was 3 wt%. The reaction temperature of the hydrogenation reaction was 270°C, the reaction pressure was 2 MPa, the mass space velocity was 0.9 h -1 , and the volume ratio of hydrogen to oil was 360:1.

[0090] Example 2

[0091] The molar ratio of the raw materials AlCl3, TiCl4, and triethylamine hydrochloride for preparing the modified ionic liquid catalyst was 1.8:0.3:1. The polymerization reaction conditions for the one-pass and full-cycle evaluation processes were both a reaction pressure of 2.0 MPa and a reaction temperature of 150°C. In the oligomerization reaction, the mass ratio of the modified ionic liquid catalyst to dry olefins was 10:100, and the reaction time was 25 min.

[0092] The pressure in the primary fractionating tower was controlled at 0.1 MPa. The feed temperature of the stabilizing tower was 215°C, and the pressure in the tower was controlled at 0.1 MPa.

[0093] In this embodiment, the pressure in the first low-pressure separation tank was 0.08 MPa, and the pressure in the second low-pressure separation tank was 0.08 MPa.

[0094] In the hydrogenation reaction, the hydrogenation catalyst was a Mo-modified nickel catalyst. The content of nickel in the hydrogenation catalyst was 20 wt%, and the content of Mo was 1.5 wt%. The reaction temperature of the hydrogenation reaction was 200°C, the reaction pressure was 4 MPa, the mass space velocity was 0.7 h -1 , and the volume ratio of hydrogen to oil was 500:1.

[0095] Example 3

[0096] The molar ratio of the raw materials AlCl3, TiCl4, and triethylamine hydrochloride for preparing the modified ionic liquid catalyst was 2.2:0.4:1. The polymerization reaction conditions for the one-pass and full-cycle evaluation processes were both a reaction pressure of 6.0 MPa and a reaction temperature of 60°C. In the oligomerization reaction, the mass ratio of the modified ionic liquid catalyst to dry olefins was 5:100, and the reaction time was 30 min.

[0097] The pressure in the primary fraction column was controlled at 0.1 MPa. The feed temperature of the stabilizing column was 225°C, and the pressure in the column was controlled at 0.1 MPa.

[0098] In this embodiment, the pressure in the first low-pressure separation tank was 0.05 MPa, and the pressure in the second low-pressure separation tank was 0.05 MPa.

[0099] In the hydrogenation reaction, a W-modified nickel catalyst was used as the hydrogenation catalyst. In the hydrogenation catalyst, the content of nickel was 40 wt%, and the content of W was 4 wt%. The reaction temperature of the hydrogenation reaction was 150°C, the reaction pressure was 8 MPa, the mass space velocity was 0.2 h -1 , and the volume ratio of hydrogen to oil was 300:1.

[0100] It can be understood that the tubular reactor can also be used to replace the stirred reaction kettle as the polymerization reactor in Embodiments 1-3. When the tubular reactor is used, the tubular reactor needs to be filled with packing. The material of the packing is ceramic, corundum, quartz or inert alumina. The shape of the packing is at least one of a spherical shape, a ring shape or a saddle shape.

[0101] Embodiment 4

[0102] The evaluation process of the catalytic activity of the modified ionic liquid catalyst was carried out in the column reactor 76.

[0103] Please refer to Figure 3 The evaluation process of one-time passing was that the green olefins 101 as the raw material were dehydrated to a water content <5 PPM by the dryer 31 filled with 3A molecular sieves under the action of the raw material pump 11, to form dry olefins.

[0104] The dry olefins were heated by the refrigerant channel of the raw material heat exchanger 51, entered the column reactor 76 from the bottom, the fresh modified ionic liquid catalyst entered the column reactor from the top, the dry olefins and the modified ionic liquid catalyst were countercurrently contacted and carried out oligomerization reaction to form a reaction mixture.

[0105] The reaction mixture entrained with the modified ionic liquid catalyst went out from the top of the column reactor, was cooled by the heating medium channel of the raw material heat exchanger 51, and then entered the settling tank 33 for separation. The separated modified ionic liquid catalyst was discharged from the bottom of the settling tank for recycling, and the separated reaction mixture 331 was discharged from the top of the settling tank. After detecting the components in the reaction mixture, the catalytic activity of the modified ionic liquid catalyst was evaluated.

[0106] Please refer to Figure 4 The evaluation process of the full circulation of light and heavy components was as follows:

[0107] (1) Under the action of the raw material pump 11, the green olefins 101 as raw materials are dehydrated together with the first separated components, the second separated components and the light components recycled back through the dryer filled with 3A molecular sieves to a water content <5PPm, forming dry olefins.

[0108] (2) The dry olefins are heated after passing through the coolant channel of the raw material heat exchanger 51, mixed with the heavy components recycled back, and then enter the tower reactor from the lower part, while the modified ionic liquid catalyst enters the tower reactor from the upper part. The dry olefins and the modified ionic liquid catalyst are countercurrently contacted and undergo oligomerization reaction to form a reaction mixture.

[0109] Among them, the fresh modified ionic liquid catalyst 102 is pumped into the tower reactor by the catalyst pump 12, and most of the modified ionic liquid catalyst is discharged from the bottom of the tower reactor and then returned to the tower reactor from the top.

[0110] (3) The reaction mixture entraining the modified ionic liquid catalyst is discharged from the top of the tower reactor, cooled by the heating medium channel of the raw material heat exchanger 51, and then enters the settling tank 33 for separation. The modified ionic liquid catalyst is discharged from the bottom of the settling tank and mixed with the modified ionic liquid catalyst discharged from the bottom of the tower reactor in step (2), and then returned to the tower reactor by the first circulating pump for recycling. The reaction product is discharged from the top of the settling tank and then enters the first high-pressure separation tank.

[0111] It can be understood that in another embodiment, the modified ionic liquid catalyst discharged from the bottom of the tower reactor and the modified ionic liquid catalyst discharged from the bottom of the settling tank can be returned to the tower reactor by a first circulating pump, respectively.

[0112] (4) The first separated components rich in C2 olefins discharged from the tank top of the first high-pressure separation tank 34 enter the first buffer tank 52 and are mixed with the second separated components described below, and then are compressed by the first compressor 21 and mixed with the green olefins and the light components described below, and then are returned to the stirred reaction kettle 32 to continue to participate in the reaction. The high components discharged from the tank bottom of the first high-pressure separation tank 34 enter the first low-pressure separation tank 35. The pressure in the first high-pressure separation tank is provided by the pressure carried by the reaction product itself.

[0113] (5) The second separated components rich in C3 and C4 olefins discharged from the tank top of the first low-pressure separation tank 35 also enter the first buffer tank and are mixed with the first separated components, and then are returned to the stirred reaction kettle by the first compressor 21 to continue to participate in the reaction. The polymerization product discharged from the tank bottom of the first low-pressure separation tank 35 enters the primary separation column 36. In this application, the pressure in the first low-pressure separation tank is 0.05-0.1 MPa, and in this embodiment, the pressure in the first low-pressure separation tank is 0.1 MPa.

[0114] The first buffer tank buffers the pressure and flow of the first separated component and the second separated component, and separates a small amount of liquid carried by the first separated component and the second component. The separated liquid in the first buffer tank is discharged from the bottom of the first buffer tank and enters a waste water treatment system for harmless treatment.

[0115] (6) The primary fractionating column is a fractionating column, and the polymerization product enters the primary fractionating column from the middle. The feed temperature is 250°C, the overhead temperature is controlled at 150±3°C, the bottom temperature is controlled at 295-300°C, and the pressure in the column is 0.05-0.1 MPa. The light component is discharged from the overhead of the primary fractionating column 36 and enters the first reflux tank. Part of the condensate in the first reflux tank is returned to the primary fractionating column, and the other part is mixed with the green olefins and the first separated component and the second separated component by the action of the second circulating pump 14, and is used as raw material together, and after drying by the dryer 31, is returned to the stirred reaction kettle 32 to continue to participate in the reaction. The middle component is discharged from the middle side line 363 of the primary fractionating column and enters the water washing column 37. The heavy component is discharged from the bottom of the primary fractionating column 36 and is divided into two streams. One of the streams is returned to the primary fractionating column after being heated by the first reboiler, and the other stream is returned to the polymerization reactor by the action of the third circulating pump 15 to continue to participate in the reaction.

[0116] It can be understood that in other embodiments, the primary fractionating column can also be composed of two fractionating columns connected in series. The specific structure is described in the related description of Embodiment 1, and is not repeated here.

[0117] (7) The middle component enters the water washing column 37 from the lower part and flows upward, and is countercurrently contacted with the washing water 61 entering from the upper part of the water washing column to wash. In the present application, the temperature of the water washing column is controlled in the range of 50-90°C, and the water-oil ratio is in the range of (3-5):1. In the present embodiment, the water washing temperature is 80°C, and the water-oil ratio is 4:1.

[0118] After washing, the middle component is heated by the coolant channel of the second heat exchanger 53 and the heating furnace 54 in turn, and then enters the hydrogenation reactor 38 to perform hydrogenation reaction to form a hydrogenation product. New hydrogen 103 is added to the washed middle component by the second compressor 22.

[0119] In the hydrogenation reactor, the organic chlorides in the middle component become hydrogen chloride and alkanes. The waste water discharged from the bottom of the water washing column enters a waste water treatment system for harmless treatment.

[0120] (8) The hydrogenation product enters the dechlorination reactor 39 filled with dechlorination agent, and the hydrogen chloride reacts with the zinc oxide in the dechlorination agent to produce zinc chloride, so that the hydrogen chloride is fixed on the dechlorination agent, and the hydrogenation product becomes a dechlorination product. The dechlorination product is cooled by the heat medium channel of the second heat exchanger, and then is subjected to high pressure separation and low pressure separation by the second high pressure separation tank 40 and the second low pressure separation tank 41 in turn.

[0121] In this embodiment, the dechlorination agent specifically adopts zinc oxide-based dechlorination agent. The dechlorination agent in this embodiment is prepared by the following method: 30wt% zinc oxide, 30wt% calcium oxide, 20wt% aluminum oxide and 20wt% kaolin are uniformly mixed, then extruded into a strip with a diameter of 5mm, then activated at 70°C for 9h, then activated at 350°C for 3h, and finally sieved with 10 mesh to obtain the dechlorination agent.

[0122] It can be understood that in other embodiments, commercially available zinc oxide-based dechlorination agents such as T408 type dechlorination agent of Northwest Chemical Research Institute Co., Ltd. can also be used.

[0123] The hydrogen gas separated from the top of the second high-pressure separation tank is buffered in the second buffer tank 55, mixed with fresh hydrogen, and returned to the hydrogenation reactor under the action of the second compressor for recycling. The liquid separated in the second buffer tank enters the waste water treatment system for harmless treatment.

[0124] The liquid discharged from the bottom of the second high-pressure separation tank enters the second low-pressure separation tank. The crude hydrogen 111 separated from the top of the second low-pressure separation tank is burned in a flare. The pressure in the second high-pressure separation tank is provided by the dechlorination product itself. In this application, the pressure in the second low-pressure separation tank is 0.05-0.1 MPa. Specifically, in this embodiment, the pressure in the first low-pressure separation tank is 0.1 MPa.

[0125] (9) The liquid phase product separated from the bottom of the second low-pressure separation tank enters the middle of the stabilizing column 42. The gas phase product 112 separated from the top of the stabilizing column is sent to a flare. The product separated from the bottom of the stabilizing column is the SAF product 113. In this application, the stabilizing column is a fractional distillation column. The liquid phase product enters the middle of the column at a temperature of 210-230°C. The top temperature of the column is controlled at 150±3°C, and the bottom temperature of the column is controlled at 220±3°C. The pressure in the column is 0.05-0.1 MPa. Specifically, in this embodiment, the pressure in the column of the stabilizing column is controlled at 0.06-0.08 MPa. It can be understood that in other embodiments, the pressure in the column of the stabilizing column can also be controlled at 0.05-0.07 MPa or 0.09-0.1 MPa, or other pressure intervals or point values within 0.05-0.1 MPa, or other pressure intervals or point values.

[0126] A second reflux tank is arranged at the top of the stabilizing tower, the product discharged from the top of the stabilizing tower first enters the second reflux tank 421, the condensate in the second reflux tank returns to the stabilizing tower, and the gas phase product 112 discharged from the top of the second reflux tank goes to a flare. A second reboiler 422 is arranged at the bottom of the stabilizing tower, the tower bottom material is discharged and divided into two streams, one of which is heated by the second reboiler 422 and then returned to the stabilizing tower, and the other stream is used as the SAF product 113.

[0127] The molar ratio of the raw materials AlCl3, TiCl4 and triethylamine hydrochloride for preparing the modified ionic liquid catalyst is 2:0.2:1, the polymerization reaction conditions in the one-time through and full cycle evaluation processes are that the reaction pressure is 4.0 MPa and the reaction temperature is 70℃, and when the oligomerization reaction is performed, the mass ratio of the modified ionic liquid catalyst to dry olefin is 20:100, and the reaction time is 20 min.

[0128] When the hydrogenation reaction is performed, the hydrogenation catalyst is a nickel-based catalyst modified by Mo, the content of nickel in the hydrogenation catalyst is 35wt%, the content of Mo is 3wt%, the reaction temperature of the hydrogenation reaction is 270℃, the reaction pressure is 2MPa, the mass space velocity is 0.9h -1 , and the volume ratio of hydrogen to oil is 360:1.

[0129] Comparative Example 1

[0130] The comparative example is basically the same as Example 1, and the only difference is that the modified ionic liquid catalyst is different, in the comparative example, the modified ionic liquid catalyst is only made of AlCl3 and triethylamine hydrochloride, and the molar ratio of AlCl3 to triethylamine hydrochloride is 2:1.

[0131] Comparative Example 2

[0132] The comparative example is basically the same as Example 1, and the only difference is that the amount of the modifier added in the modified ionic liquid catalyst is different, in the comparative example, the molar ratio of AlCl3, TiCl4 and triethylamine hydrochloride is 2:0.6:1.

[0133] Comparative Example 3

[0134] The comparative example is basically the same as Example 1, and the only difference is that the amount of the modifier added in the modified ionic liquid catalyst is different, in the comparative example, the molar ratio of AlCl3, TiCl4 and triethylamine hydrochloride is 2:0.08:1.

[0135] The top outlet of the settling tank in each example and comparative example is sampled, and after water washing, the reaction performance analysis data is obtained and listed in Table 1.

[0136] Table 1 Reaction performance analysis data

[0137]

[0138] From the results of sampling analysis at the top outlet of the settling tank, it can be seen from Table 1 that, compared with the unmodified ionic liquid catalyst, the conversion of green olefins is slightly increased, but the selectivity of light components is greatly reduced, the selectivity of heavy components is slightly increased, and the selectivity of the final SAF product is increased when the modified ionic liquid catalyst is used. It is indicated that the TiCl n After modification, the catalytic activity of the ionic liquid catalyst is improved.

[0139] From Table 1, it can also be seen that the appropriate proportion of TiCl n is conducive to achieving the desired effect. When the modifier TiCl n is too little, the acidity of the catalyst is still too high, the selectivity of light components of the product is too high, and the selectivity of the SAF is too low; when the modifier TiCl n is too much, the acidity of the catalyst is too low, the conversion rate is slightly decreased, the content of the dichloro bridge structure of Ti and A is high, the polymerization depth is increased, the selectivity of heavy components is high, and the selectivity of the SAF is reduced.

[0140] From the results of sampling analysis at the top outlet of the settling tank, it can be seen from Table 1 that, compared with the unmodified ionic liquid catalyst, the conversion of green olefins is slightly increased, but the selectivity of light components is greatly reduced, the selectivity of heavy components is slightly increased, and the selectivity of the final SAF product is increased when the modified ionic liquid catalyst is used. It is indicated that the TiCl

[0141] The biggest advantage of the full circulation process is that the light and heavy components are not products, but continue to circulate, and only the SAF product is discharged from the device, i.e. almost 99% or more of the raw materials are converted into the final SAF product, realizing the maximum economic utilization of raw materials.

[0142] The SAF products obtained by the full circulation process in each example and comparative example are analyzed, and the specific data are listed in Table 2.

[0143] Table 2 Analysis data of the final SAF product

[0144]

[0145] From the final product analysis, it can be seen that the products all meet the requirements of the SAF, but the products of the unmodified catalyst and the low-modified catalyst are slightly light, and the products of the high-modified catalyst are slightly heavy.

Claims

1. A method for producing SAF from green olefins, characterized in that, Includes the following steps: (1) The raw material green olefins, the first separation component, the second separation component, and the light component returned from the recycling are dehydrated in a dryer to form dry olefins; (2) The dried olefins and the recycled heavy components enter the polymerization reactor and undergo oligomerization under the action of the modified ionic liquid catalyst to form a reaction mixture; (3) The reaction mixture carries the modified ionic liquid catalyst into the settling tank for separation. The separated modified ionic liquid catalyst is discharged from the bottom of the settling tank and returned to the polymerization reactor for recycling. The separated reaction products are discharged from the top of the settling tank and enter the first high-pressure separation tank. (4) The first separated component discharged from the top of the first high-pressure separator is returned to the polymerization reactor to continue to participate in the reaction, while the high-pressure component discharged from the bottom of the first high-pressure separator enters the first low-pressure separator. (5) The second separated component discharged from the top of the first low-pressure separator is returned to the polymerization reactor to continue to participate in the reaction, and the polymerization product discharged from the bottom of the first low-pressure separator enters the primary separation tower. (6) The light components are discharged from the top of the primary separator and returned to the polymerization reactor to continue to participate in the reaction; the intermediate components are discharged from the middle of the primary separator; and the heavy components are discharged from the bottom of the primary separator and returned to the polymerization reactor to continue to participate in the reaction. (7) The intermediate components are washed with water and then enter the hydrogenation reactor to carry out the hydrogenation reaction to form hydrogenation products; Inside the hydrogenation reactor, the organic chlorides in the intermediate components are converted into hydrogen chloride and alkanes; (8) The hydrogenation product enters the dechlorination reactor filled with dechlorination agent. The hydrogen chloride reacts with the zinc oxide in the dechlorination agent to generate zinc chloride, which fixes the hydrogen chloride on the dechlorination agent. The hydrogenation product becomes the dechlorination product. The dechlorination product is then separated into a second high-pressure separator and a second low-pressure separator for high-pressure separation and low-pressure separation, respectively. The hydrogen separated from the top of the second high-pressure separator is returned to the hydrogenation reactor for recycling, and the crude hydrogen separated from the top of the second low-pressure separator is burned in the flare. (9) The liquid phase product separated from the bottom of the second low-pressure separator enters the stabilizer, the gas phase product separated from the top of the stabilizer goes to the flare, and the product separated from the bottom of the stabilizer is the SAF product.

2. The production method according to claim 1, characterized in that, The green olefin is produced by dehydration of biomass alcohol or green methanol. The green olefin contains 0.1-50 wt% ethylene, 30-70 wt% propylene, and 5-30 wt% butene.

3. The production method according to claim 1, characterized in that, In step (1), dehydration is performed using a molecular sieve, which is at least one of 3A, 4A, 5A or 13X.

4. The production method according to claim 1, characterized in that, In step (2), the polymerization reactor is a tubular reactor, a stirred tank reactor, or a tower reactor; When the polymerization reactor is a tubular reactor, the tubular reactor is filled with packing material, which is ceramic, corundum, quartz or inert alumina, and the shape of the packing is at least one of spherical, annular or saddle-shaped.

5. The production method according to claim 4, characterized in that, In step (2), during the oligomerization reaction, the reaction pressure is 2.0-6.0 MPa, the reaction temperature is 50-150℃, the mass ratio of the modified ionic liquid catalyst to the dry olefin is (2-20):100, and the reaction time is 1-30 min.

6. The production method according to claim 1, characterized in that, In step (2), the cation in the modified ionic liquid catalyst is at least one of imidazole cations, quaternary ammonium cations, or pyridine cations, and the anion is AlCl4. - / Al2Cl7 - The modifier is TiCl n .

7. The production method according to claim 6, characterized in that, In the modified ionic liquid catalyst, the molar ratio of cations to anions is 1:(1.5-2.5).

8. The production method according to claim 6, characterized in that, In the modified ionic liquid catalyst, the molar ratio of Ti to Al is (0.05-0.2):

1.

9. The production method according to claim 6, characterized in that, The method for preparing this modified ionic liquid catalyst is as follows: Under a nitrogen atmosphere, cationic chloride and AlCl3 were added to the synthesis reactor and stirred. The reaction was carried out at 70-120℃ for 0.5-10 hours, after which TiCl3 was added. n The reaction was continued for 1-5 hours to obtain the modified ionic liquid catalyst.

10. The production method according to claim 1, characterized in that, In step (7), the hydrogenation reactor is a fixed-bed reactor, and the hydrogenation catalyst is a Mo or W modified nickel-based catalyst. In the hydrogenation catalyst, the nickel content is 15-50 wt%, and the Mo or W content is 1-5 wt%. The reaction temperature of the hydrogenation reaction is 150-280℃, the reaction pressure is 2.0-8.0 MPa, and the mass hourly space velocity is 0.2-1.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is (300-500):1.

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