A method for de-olefinating a reformulated oil

Abstract

The present application relates to the field of petrochemical, and discloses a method for removing olefins from reformate, comprising: A) hydrogen is first introduced into a hydrogenation reactor to reduce and pretreat a hydrogenation catalyst; B) the reformate is transported from a reforming device to a de-pentane column, and after being treated by the de-pentane column, the column bottom oil is transported to the hydrogenation reactor; C) under the condition of hydrogen, the material in the hydrogenation reactor is heated, and after hydrogenation catalytic reaction, the removal of olefins from the reformate is completed. The self-made hydrogenation catalyst is used for hydrogenation catalysis of the reformate to achieve the purpose of removing olefins. In the hydrogenation catalytic removal of olefins from the reformate, the hydrogenation catalyst has the advantages of high catalytic activity, high olefin hydrogenation selectivity, low carbon deposition and low cost, so that the loss of aromatic hydrocarbons in the process of removing olefins from the reformate can be effectively reduced, the efficiency of removing olefins can be improved, and the service life can be significantly prolonged.

Description

Technical Field

[0001] This invention relates to the petrochemical field, and more particularly to a method for deolefination of reforming oil. Background Technology

[0002] Benzene, toluene, xylene (BTX), and other aromatic hydrocarbons are important chemical raw materials with wide applications in various fields related to human necessities. Catalytic reforming technology can convert naphtha into reformate oil rich in BTX. With the continuous development of catalytic reforming technology, the BTX content in reformate oil has been significantly increased; however, the content of olefin impurities in the reformate oil has also increased. Olefin impurities not only affect the bromine value and acid washing color of BTX products, but also polymerize in the extraction solvent during the extraction and separation of BTX from the reformate oil, thus contaminating the extraction solvent and corroding the equipment. Therefore, to produce qualified BTX products, it is essential to first remove olefins from the reformate oil and reduce their content as much as possible.

[0003] In existing technologies, the main methods for removing olefins from reforming oils include:

[0004] (1) Catalytic adsorption method, which involves adsorbing olefins in reformed oil using adsorbents such as molecular sieves, clay, and modified clay. The disadvantages of this method are that the adsorbents have a short service life and need to be replaced frequently, and many types of adsorbents are for single use only and cannot be regenerated.

[0005] (2) Hydrocatalysis, which uses catalysts containing precious metal active components to hydrogenate reformed oil, converting olefins into alkanes. The disadvantages of this method are the high cost of precious metal catalysts and their tendency to deactivate due to carbon buildup during catalysis, requiring frequent maintenance. To reduce catalyst costs, researchers have gradually developed catalysts with non-precious metal active components. However, these catalysts generally require high reaction temperatures and low volume hourly space ratios for catalytic reactions, resulting in significant aromatic losses, high energy consumption, and the persistent problem of carbon buildup.

[0006] In summary, it would be of great significance to develop a new process for deolefin removal from reforming oil that is low-cost, has high catalytic efficiency in olefin hydrogenation, low aromatic loss, and is not prone to carbon buildup. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a method for deolefin removal from reforming oil. This invention employs a self-made hydrogenation catalyst to catalyze the hydrogenation of reforming oil to achieve deolefin removal. This hydrogenation catalyst exhibits advantages such as high catalytic activity, high selectivity for olefin hydrogenation, low carbon deposition, and low cost in the deolefin removal reaction of reforming oil. Therefore, it can effectively reduce aromatic hydrocarbon loss in the deolefin removal process of reforming oil, improve deolefin removal efficiency, and significantly extend service life.

[0008] The specific technical solution of this invention is: a method for deolefination of reformed oil, comprising the following steps:

[0009] A) A hydrogenation catalyst is loaded into a hydrogenation reactor. Hydrogen gas is first introduced into the hydrogenation reactor to reduce and pretreat the hydrogenation catalyst. The hydrogenation catalyst uses alumina as a support and single-crystal Ni particles, Ni-Si and Ni-Si / SiO2 supported on the support as active components. Ni-Si and Ni-Si / SiO2 are distributed between the single-crystal Ni particles.

[0010] B) The reformed oil is transported from the reforming unit to the depentanizer. After processing in the depentanizer, the bottom oil from the depentanizer is transported to the hydrotreating reactor.

[0011] C) Under hydrogen gas conditions, the material in the hydrogenation reactor is heated, and after hydrogenation catalytic reaction, the deolefinization treatment of the reformed oil is completed.

[0012] In step A), the present invention first performs a reduction pretreatment on the hydrogenation catalyst in the hydrogenation reactor, which can activate the hydrogenation catalyst and improve its catalytic hydrogenation performance. In step B), the present invention sends the reformate to a depentanizer for processing to remove C5 and below light hydrocarbons, thereby reducing the impact of these light hydrocarbon molecules on the catalyst and the reformate. In step C), the present invention performs a formal deolefinization treatment on the reformate, using a self-made hydrogenation catalyst for deolefinization. Specifically:

[0013] The hydrogenation catalyst of this invention uses alumina as a support, on which single-crystal Ni particles, Ni-Si, and Ni-Si / SiO2 are uniformly loaded (as the silicide temperature increases, the formed silicides follow the following pattern: Ni2Si, NiSi, NiSi2; in this invention's catalyst, Ni-Si represents a mixture of the above compounds, with NiSi being the predominant component), and a large number of single-crystal Ni particles are separated by Ni-Si and Ni-Si / SiO2. In the process of Ni-catalyzed reforming of oil for hydrodeolefins, generally, the smaller the single-crystal Ni particle size, the better the dispersion, and the higher the hydrogenation activity. In this invention's catalyst, some Ni combines with Si to form Ni-Si, which plays a certain role in isolating the single-crystal Ni particles, reducing the Ni particle size, and improving the reaction activity. More importantly, we also found that the above-mentioned barrier effect can significantly improve the selectivity of the catalyst for olefin hydrogenation. The reason is that reformed oil mainly consists of aromatics and a small amount of olefins. In the hydrodeolefins process, olefins are adsorbed on a single site, meaning they can be activated and undergo hydrogenation after occupying one active site on the catalyst. Aromatics, on the other hand, are adsorbed on multiple sites, requiring multiple active sites on the catalyst to be hydrogenated. In this invention, due to the spacer effect of the Ni-Si compound on the single-crystal Ni particles, different active sites are spaced far apart. Aromatic molecules are less likely to simultaneously occupy multiple active sites on single-crystal Ni. Therefore, while improving the reactivity of olefins, the reactivity of aromatic molecules can be effectively reduced, improving the selectivity of hydrodeolefins in reformed oil and thus reducing aromatic loss. At the same time, the spacer effect of the Ni-Si compound on the single-crystal Ni particles also prevents them from binding together, thus avoiding a reduction in active sites for olefin hydrogenation, thereby delaying deactivation or coking and effectively extending the catalyst's lifespan.

[0014] Furthermore, the reason for choosing Ni-Si and Ni-Si / SiO2 in this invention is that they can readjust the catalytic activity of the catalyst in the olefin hydrogenation reaction. (1) First, in the Ni-Si compound, when Si atoms are inserted into the Ni lattice, the d-orbitals of Ni atoms and the p-orbitals of Si atoms interact, resulting in a decrease in the integer of the energy level jump, a narrowing of the d-band, and a shift of the resonance energy level towards the direction of higher binding energy. This leads to coupling between the energy state of Si and the Ni orbital, ultimately forming a unique bonded state that is more compact than the original two states. Since filling these bonded orbitals leads to bond strengthening, the Ni-Si compound has high electrical and thermal conductivity and strong stability. Moreover, the geometry and electronic structure of Ni are changed, thus exhibiting good reactivity and high chemical stability; (2) Second, this invention found that Ni-Si and SiO2 in Ni-Si / SiO2 have strong interactions in the olefin hydrogenation reaction. This strong interaction refers to a special synergistic effect existing at the Ni-Si and SiO2 interface. Essentially, it involves charge redistribution and mass transfer at the Ni-Si and SiO2 interface, thereby altering the electronic structure and morphology of the catalyst. This, in turn, affects the adsorption behavior of reactants and the formation of reaction intermediates, ultimately changing the overall reaction pathway and the catalytic performance of the catalyst. When Ni-Si and SiO2 are combined, charge redistribution occurs at the Ni-Si and SiO2 interface, thus changing the electronic structure and morphology of the catalyst. Specifically, after Ni-Si and SiO2 combine, SiO2 transfers some charge to Ni-Si and can affect the electron cloud density of the adsorbed gas, thereby regulating the catalytic activity of the catalyst. Our research team has found that the strongly interacting Ni-Si / SiO2 can promote hydrogen adsorption and improve reaction activity in the hydrogenation catalytic reaction of reforming oil, and is beneficial in reducing the formation of byproducts such as polyolefins and heavy aromatics, thereby reducing the risk of catalyst carbon deposition.

[0015] Preferably, in step A), the reduction pretreatment conditions are as follows: under a pressure of 0.8-1.2 MPa, the temperature is increased from room temperature to 400℃ at a heating rate of 1.5-2.5℃ / min, and the reduction pretreatment lasts for 3-5 hours.

[0016] Preferably, in step B), the process parameters of the depentanizer are: top pressure 0.93-0.98 MPa, top temperature 85-90℃, bottom temperature 210-220℃, tray temperature 140-180℃, and reflux ratio 0.2-0.3.

[0017] Preferably, in step C), the conditions for the hydrogenation catalytic reaction are: a reaction temperature of 120-140°C, a reaction pressure of 1.0-1.2 MPa, and a volume hourly space velocity of 8-12 h⁻¹. -1The hydrogen-to-oil ratio is 21-25:1.

[0018] Preferably, in step A), the specific surface area of ​​the hydrogenation catalyst is 150-260 m². 2 / g, pore volume 0.3-0.7cm³ 3 / g, of which pores with a diameter of 5-10nm account for 60-80% of the total pore volume of the catalyst.

[0019] Preferably, in step A), the hydrogenation catalyst is prepared by the following method:

[0020] 1) SiO2 powder is uniformly dispersed in modified nickel solution, the system is adjusted to be alkaline, heated to react, and the reaction product is obtained by post-treatment separation. The product is then calcined and pulverized to obtain NiO / SiO2 composite powder.

[0021] 2) Mix the product obtained in step 1) with alumina powder, add Ni(NO3)2 aqueous solution to the mixture and stir until it becomes a paste, dry, grind, press into tablets, and calcine to obtain alumina loaded with NiO and NiO / SiO2.

[0022] 3) The product obtained in step 3) is first reduced in a reducing atmosphere, then silicided in an atmosphere containing SiH4 / H2, and finally reduced again in a reducing atmosphere and cooled to obtain alumina loaded with single-crystal Ni particles, Ni-Si and Ni-Si / SiO2, which is the hydrogenation catalyst.

[0023] In step 1) above, the modified nickel solution contains nickel acetylacetonate, and ethylene glycol acts as a solvent and dispersant. After adding SiO2 powder and mixing, the pH is adjusted to alkaline and heated to react. At this time, nickel acetylacetonate undergoes a hydrolysis reaction, and nickel hydroxide is precipitated from the solvent and uniformly deposited or adsorbed onto the surface of SiO2 powder. After post-treatment to remove the solvent and the generated organic byproducts, calcination can dehydrate the nickel hydroxide to generate nickel oxide and further remove impurities. It can also make the nickel oxide firmly loaded on SiO2. After pulverization, NiO / SiO2 composite powder can be obtained.

[0024] In step 2) above, the paste contains alumina, NiO / SiO2 composite powder, Ni(NO3)2 and water. After drying to remove the water, the resulting solid mixture is ground, pressed into tablets, and then calcined. At this time, the Ni(NO3)2 contained in the solid mixture undergoes a decomposition reaction at high temperature to produce NiO, which is loaded onto the alumina and NiO / SiO2 composite powder, thereby obtaining alumina loaded with NiO and NiO / SiO2.

[0025] This invention employs a two-step method to load Ni onto the catalyst, specifically in steps 1) and 2). The main reasons for this are as follows: First, if all Ni is added in step 1), the resulting NiO / SiO2 composite powder will have an excessively high NiO content, easily forming flakes on SiO2, and the produced NiO particles will be too large. Consequently, in step 2), NiO cannot be effectively and uniformly dispersed, severely reducing the role of Ni in the catalyst. Second, if all Ni is added in step 2), i.e., after mixing alumina powder with SiO2, an aqueous solution of nickel nitrate containing all Ni is added, although this can produce alumina loaded with uniformly dispersed NiO, it will result in a relatively low NiO content adsorbed on SiO2. This leads to insufficient Ni-Si / SiO2 components generated in step 3), failing to effectively achieve a strong interaction effect.

[0026] In step 3) above, under high-temperature reducing atmosphere conditions, NiO is first reduced to single Ni metal particles, and then some Ni reacts with silane to generate Ni metal silicide (denoted as Ni-Si compound). First, Ni-Si can block single crystal Ni particles, thereby improving the selectivity and service life of the catalyst; second, Ni-Si and SiO2 have a strong interaction effect, which can regulate the catalytic performance.

[0027] Preferably, in step 1), the NiO content in the NiO / SiO2 composite powder is 20-30 wt%.

[0028] If the above ratio is too high, the NiO grains supported in SiO2 will be too large, or even connected into sheets, and cannot be effectively dispersed, affecting the catalytic effect; if the ratio is too low, the final catalyst will have too little Ni-Si / SiO2 content, and will not play the role of using strong interactions to improve the reaction effect.

[0029] Preferably, in step 1), the modified nickel solution is an ethylene glycol solution of nickel acetylacetonate, and the mass ratio of ethylene glycol to nickel acetylacetonate is 20-30:1.

[0030] Preferably, in step 1), the alkaline pH is 9-10; the reaction temperature is 110-130℃ and the time is 1-2h; the post-treatment is cooling, filtering, and washing until neutral; and the calcination temperature is 500-600℃ and the time is 2-3h.

[0031] In step 1), calcination at this temperature can remove moisture, including adsorbed water and crystal water of NiO, and load NiO onto SiO2, preventing sintering, while maintaining high reactivity of NiO and making it easier for hydrogen to reduce it.

[0032] Preferably, in step 2), the content of Al2O3 in the alumina loaded with NiO and NiO / SiO2 is 60-70 wt%, the content of NiO is 20-30 wt%, and the content of SiO2 is 10-20 wt%.

[0033] If the NiO content is too high, it will easily cause the Ni particles to aggregate, resulting in excessively large Ni particle size in the catalyst and affecting the catalytic effect. If the NiO content is too low, the Ni particle content in the catalyst will be too low, affecting the catalytic activity. If the SiO2 content is too high, there will be a large amount of relatively large Ni-Si / SiO2 particles in the catalyst, which is not conducive to the diffusion of reactant gases in the catalyst and also affects the uniform distribution of Ni. If the SiO2 content is too low, the Ni-Si / SiO2 content in the catalyst will be too low, and the strong interaction effect cannot be effectively exerted.

[0034] Preferably, in step 2), the drying temperature is 100-120℃ and the time is 10-15h; the calcination temperature is 500-600℃ and the time is 4-6h.

[0035] In step 2), the above calcination conditions can further remove moisture, decompose Ni(NO3)2 to generate NiO, maintain the reactivity of NiO, and not change the performance of NiO on the original SiO2 support.

[0036] Preferably, in step 3), the alumina loaded with NiO and NiO / SiO2 is first slowly heated to 350-380℃ in a hydrogen atmosphere for 4-6 hours for reduction, then silicided in a SiH4 / H2 atmosphere for 20-30 minutes, and finally cooled to room temperature in a hydrogen atmosphere; the volume percentage of SiH4 in the SiH4 / H2 atmosphere is 5-15%.

[0037] Compared with the prior art, the present invention has the following technical effects: The present invention uses a self-made hydrogenation catalyst to hydrogenate reformate oil to achieve the purpose of de-olefination. In the de-olefination reaction of reformate oil hydrogenation catalysis, the hydrogenation catalyst has the advantages of high catalytic activity, high olefin hydrogenation selectivity, low carbon deposition and low cost, thereby effectively reducing aromatic loss in the de-olefination process of reformate oil, improving de-olefination efficiency and significantly extending service life. Detailed Implementation

[0038] The present invention will be further described below with reference to embodiments.

[0039] General Implementation Examples

[0040] A method for deolefin removal from reforming oil includes the following steps:

[0041] A) The hydrogenation catalyst is loaded into the hydrogenation reactor. Hydrogen gas is first introduced into the hydrogenation reactor to reduce the hydrogenation catalyst for pretreatment. The process conditions are: at a pressure of 0.8-1.2 MPa, the temperature is increased from room temperature to 400℃ at a heating rate of 1.5-2.5℃ / min, and the reduction pretreatment lasts for 3-5 hours.

[0042] B) The reformed oil is transported from the reforming unit to the depentanizer. The process parameters of the depentanizer are: top pressure 0.93-0.98 MPa, top temperature 85-90℃, bottom temperature 210-220℃, tray temperature 140-180℃, and reflux ratio 0.2-0.3. After being processed by the depentanizer, the bottom oil of the depentanizer is transported to the hydrotreating reactor.

[0043] C) Under hydrogen gas conditions, the material in the hydrogenation reactor is heated to carry out a hydrogenation catalytic reaction. The conditions for the hydrogenation catalytic reaction are: reaction temperature 120-140℃, reaction pressure 1.0-1.2MPa, and volume hourly space velocity 8-12h. -1 The hydrogen-to-oil ratio is 21-25:1, and the de-olefinization treatment of the reformed oil is completed after the reaction.

[0044] The hydrogenation catalyst described above uses alumina as a support, and single-crystal Ni particles, Ni-Si, and Ni-Si / SiO2 supported on the support are the active components; Ni-Si and Ni-Si / SiO2 are distributed between the single-crystal Ni particles.

[0045] Preferably, the catalyst has a specific surface area of ​​150-260 m². 2 / g, with a pore volume of 0.3-0.7cm3 / g, of which pores with a diameter of 5-10nm account for 60-80% of the total pore volume of the catalyst.

[0046] The preparation method of the above-mentioned hydrogenation catalyst includes the following steps:

[0047] 1) Mix SiO2 powder and modified nickel solution (prepared by mixing ethylene glycol and nickel acetylacetonate in a mass ratio of 20-30:1), adjust the pH to alkaline (preferably 9-10), heat the reaction (preferably 110-130℃, 1-2h), cool, filter, wash to neutral, calcine (preferably 500-600℃, 2-3h), and pulverize to obtain NiO / SiO2 composite powder (preferably NiO mass percentage is 20-30%).

[0048] 2) Al2O3 powder and NiO / SiO2 composite powder are mixed evenly, and Ni(NO3)2 aqueous solution is added and stirred into a paste. After drying (preferably 100-120℃, 10-15h), grinding, shaping, and calcining (preferably 500-600℃, 4-6h), alumina loaded with NiO / SiO2 is obtained (the mass ratio of Al2O3 is preferably 60-70%, the mass ratio of NiO is preferably 20-30%, and the mass ratio of SiO2 is preferably 10-20%).

[0049] 3) First, reduce the alumina loaded with NiO / SiO2 by slowly heating it to 350-380℃ in a hydrogen atmosphere for 4-6 hours. Then, silaneize it in an atmosphere of 5-15% SiH4 / H2 by volume for 20-30 minutes. Finally, reduce it in a hydrogen atmosphere and cool it to obtain alumina loaded with single-crystal Ni particles and Ni-Si / SiO2, which is the catalyst for hydrogenation of reforming oil.

[0050] Example 1

[0051] 1) Preparation of hydrogenation catalyst:

[0052] 1.1) Nickel acetylacetone was dissolved in ethylene glycol at a mass ratio of 1:25 to obtain a modified nickel solution. Then, under stirring, silica powder was added to the modified nickel solution at a mass ratio of 1:26. While continuing to stir, a 10% sodium carbonate aqueous solution was slowly added until the pH value was 9.5. The resulting mixture was then heated to 120°C and reacted for 1.5 h. After the reaction was completed, the mixture was cooled, filtered, washed until neutral, and then the resulting solid was calcined at 550°C for 2.5 h and then ground to obtain NiO / SiO2 composite powder (NiO mass percentage was 25.3%).

[0053] 1.2) Al2O3 dry adhesive powder and NiO / SiO2 composite powder prepared in step 1.1) were mixed evenly in a mass ratio of 3:1:6. Then, a Ni(NO3)2 aqueous solution with a concentration of 40wt% was added and stirred into a lake. The mixture was then dried at 110℃ for 12h, ground, pressed into tablets, and then calcined at 550℃ for 5h to obtain a composition (Al2O3 mass percentage 60.2%, NiO mass percentage 25.5%, SiO2 mass percentage 14.3%).

[0054] 1.3) The composition obtained in step 1.2) was slowly heated to 360°C for 5 h in H2 atmosphere, then siliconized for 25 min in a SiH4 / H2 atmosphere with a volume ratio of 10%, and then cooled to room temperature in H2 atmosphere to obtain the hydrogenation catalyst.

[0055] 2) De-olefin treatment:

[0056] 2.1) The hydrogenation catalyst is loaded into the hydrogenation reactor. Hydrogen gas is first introduced into the hydrogenation reactor to reduce the hydrogenation catalyst for pretreatment. The process conditions are: at a pressure of 1.0 MPa, the temperature is increased from room temperature to 400℃ at a heating rate of 2℃ / min, and the reduction pretreatment is carried out for 4 hours.

[0057] 2.2) The reforming product oil is transported from the reforming unit to the depentanizer. The process parameters of the depentanizer are: top pressure 0.95 MPa, top temperature 87℃, bottom temperature 215℃, tray temperature 160℃, and reflux ratio 0.2. After being processed by the depentanizer, the bottom oil of the depentanizer is transported to the hydrogenation reactor.

[0058] 2.3) Under hydrogen gas conditions, the material in the hydrogenation reactor is heated to carry out a hydrogenation catalytic reaction. The conditions for the hydrogenation catalytic reaction are: reaction temperature 130℃, reaction pressure 1.1MPa, and volume hourly space velocity 10h⁻¹. -1 The hydrogen-to-oil ratio is 23:1, and the deolefinization treatment of the reformed oil is completed after the reaction.

[0059] Example 2

[0060] 1) Preparation of hydrogenation catalyst:

[0061] 1.1) Nickel acetylacetone was dissolved in ethylene glycol at a mass ratio of 1:30 to obtain a modified nickel solution. Then, under stirring, silica powder was added to the modified nickel solution at a mass ratio of 1:22.5. While continuing to stir, a 10% sodium carbonate aqueous solution was slowly added until the pH value was 9. The resulting mixture was then heated to 110°C and reacted for 1 hour. After the reaction was completed, the mixture was cooled, filtered, washed until neutral, and then the resulting solid was heated to 500°C and calcined for 2 hours and then ground to obtain NiO / SiO2 composite powder (NiO mass percentage was 20.4%).

[0062] 1.2) Al2O3 dry adhesive powder and NiO / SiO2 composite powder prepared in step 1.1) were mixed evenly in a mass ratio of 5.6:1:8.4. Then, a Ni(NO3)2 aqueous solution with a concentration of 40wt% was added and stirred into a lake-like state. The mixture was then dried at 100℃ for 10h, ground, pressed into tablets, and then calcined at 500℃ for 4h to obtain a composition (Al2O3 mass percentage 69.7%, NiO mass percentage 20.2%, SiO2 mass percentage 10.1%).

[0063] 1.3) The composition obtained in step 1.2) was slowly heated to 350°C for 5 hours under H2 atmosphere, and then siliconized for 20 minutes by introducing a SiH4 / H2 atmosphere with a volume ratio of 10%. Then it was cooled to room temperature under H2 atmosphere to obtain the hydrogenation catalyst.

[0064] 2) De-olefin treatment:

[0065] 2.1) The hydrogenation catalyst is loaded into the hydrogenation reactor. Hydrogen gas is first introduced into the hydrogenation reactor to reduce the hydrogenation catalyst for pretreatment. The process conditions are: at a pressure of 1.0 MPa, the temperature is increased from room temperature to 400℃ at a heating rate of 2℃ / min, and the reduction pretreatment is carried out for 4 hours.

[0066] 2.2) The reforming product oil is transported from the reforming unit to the depentanizer. The process parameters of the depentanizer are: top pressure 0.95 MPa, top temperature 87℃, bottom temperature 215℃, tray temperature 160℃, and reflux ratio 0.2. After being processed by the depentanizer, the bottom oil of the depentanizer is transported to the hydrogenation reactor.

[0067] 2.3) Under hydrogen gas conditions, the material in the hydrogenation reactor is heated to carry out a hydrogenation catalytic reaction. The conditions for the hydrogenation catalytic reaction are: reaction temperature 130℃, reaction pressure 1.1MPa, and volume hourly space velocity 10h⁻¹. -1 The hydrogen-to-oil ratio is 23:1, and the deolefinization treatment of the reformed oil is completed after the reaction.

[0068] Example 3

[0069] 1) Preparation of hydrogenation catalyst:

[0070] 1.1) Nickel acetylacetone was dissolved in ethylene glycol at a mass ratio of 1:20 to obtain a modified nickel solution. Then, under stirring, silica powder was added to the modified nickel solution at a mass ratio of 1:27. While continuing to stir, a 10% sodium carbonate aqueous solution was slowly added until the pH value was 10. The resulting mixture was then heated to 130°C and reacted for 2 hours. After the reaction was completed, the mixture was cooled, filtered, washed until neutral, and then the resulting solid was heated to 600°C and calcined for 3 hours and then ground to obtain NiO / SiO2 composite powder (NiO mass percentage was 29.8%).

[0071] 1.2) Al2O3 dry adhesive powder and NiO / SiO2 composite powder prepared in step 1.1) were mixed evenly in a mass ratio of 2.1:1:2.4. Then, a Ni(NO3)2 aqueous solution with a concentration of 40wt% was added and stirred into a lake-like state. The mixture was then dried at 120℃ for 15h, ground, pressed into tablets, and then calcined at 600℃ for 6h to obtain a composition (Al2O3 mass percentage 60.6%, NiO mass percentage 20.6%, SiO2 mass percentage 18.8%).

[0072] 1.3) The composition obtained in step 1.2) was slowly heated to 380°C under H2 atmosphere for 6 hours for reduction, and then siliconized for 30 minutes by introducing a SiH4 / H2 atmosphere with a volume ratio of 10%. Then it was cooled to room temperature under H2 atmosphere to obtain the hydrogenation catalyst.

[0073] 2) De-olefin treatment:

[0074] 2.1) The hydrogenation catalyst is loaded into the hydrogenation reactor. Hydrogen gas is first introduced into the hydrogenation reactor to reduce the hydrogenation catalyst for pretreatment. The process conditions are: at a pressure of 1.0 MPa, the temperature is increased from room temperature to 400℃ at a heating rate of 2℃ / min, and the reduction pretreatment is carried out for 4 hours.

[0075] 2.2) The reforming product oil is transported from the reforming unit to the depentanizer. The process parameters of the depentanizer are: top pressure 0.95 MPa, top temperature 87℃, bottom temperature 215℃, tray temperature 160℃, and reflux ratio 0.2. After being processed by the depentanizer, the bottom oil of the depentanizer is transported to the hydrogenation reactor.

[0076] 2.3) Under hydrogen gas conditions, the material in the hydrogenation reactor is heated to carry out a hydrogenation catalytic reaction. The conditions for the hydrogenation catalytic reaction are: reaction temperature 130℃, reaction pressure 1.1MPa, and volume hourly space velocity 10h⁻¹. -1 The hydrogen-to-oil ratio is 23:1, and the deolefinization treatment of the reformed oil is completed after the reaction.

[0077] Comparative Example 1

[0078] 1) Preparation of hydrogenation catalyst:

[0079] 1.1) Al2O3 dry adhesive powder was added to a 40wt% Ni(NO3)2 aqueous solution at a mass ratio of 7:18 and stirred into a lake-like state. The mixture was then dried at 110℃ for 12 hours, ground, pressed into tablets, and then calcined at 550℃ for 5 hours to obtain a composition (Al2O3 mass percentage of 70.2% and NiO mass percentage of 29.8%).

[0080] 1.2) The composition obtained in step 1.2) was slowly heated to 360°C under H2 atmosphere for 5 hours for reduction, and then silanized for 25 minutes by introducing a SiH4 / H2 atmosphere with a volume ratio of 10%. It was then cooled to room temperature under H2 atmosphere to obtain the hydrogenation catalyst. The difference between this hydrogenation catalyst and that of Example 1 is that step 1.1) in Example 1 was omitted; that is, the prepared hydrogenation catalyst does not contain Ni-Si / SiO2, i.e., Al2O3 is used as the support, and Ni and Ni-Si are the active components.

[0081] 2) De-olefin treatment:

[0082] 2.1) The hydrogenation catalyst is loaded into the hydrogenation reactor. Hydrogen gas is first introduced into the hydrogenation reactor to reduce the hydrogenation catalyst for pretreatment. The process conditions are: at a pressure of 1.0 MPa, the temperature is increased from room temperature to 400℃ at a heating rate of 2℃ / min, and the reduction pretreatment is carried out for 4 hours.

[0083] 2.2) The reforming product oil is transported from the reforming unit to the depentanizer. The process parameters of the depentanizer are: top pressure 0.95 MPa, top temperature 87℃, bottom temperature 215℃, tray temperature 160℃, and reflux ratio 0.2. After being processed by the depentanizer, the bottom oil of the depentanizer is transported to the hydrogenation reactor.

[0084] 2.3) Under hydrogen gas conditions, the material in the hydrogenation reactor is heated to carry out a hydrogenation catalytic reaction. The conditions for the hydrogenation catalytic reaction are: reaction temperature 130℃, reaction pressure 1.1MPa, and volume hourly space velocity 10h⁻¹. -1 The hydrogen-to-oil ratio is 23:1, and the deolefinization treatment of the reformed oil is completed after the reaction.

[0085] Comparative Example 2

[0086] 1) Preparation of hydrogenation catalyst:

[0087] 1.1) Nickel acetylacetone was dissolved in ethylene glycol at a mass ratio of 1:25 to obtain a modified nickel solution. Then, under stirring, silica powder was added to the modified nickel solution at a mass ratio of 1:26. While continuing to stir, a 10% sodium carbonate aqueous solution was slowly added until the pH value was 9.5. The resulting mixture was then heated to 120°C and reacted for 1.5 h. After the reaction was completed, the mixture was cooled, filtered, washed until neutral, and then the resulting solid was calcined at 550°C for 2.5 h and then ground to obtain NiO / SiO2 composite powder (NiO mass percentage was 25.3%).

[0088] 1.2) The Al2O3 dry adhesive powder and the NiO / SiO2 composite powder prepared in step 1.1) were mixed evenly in a mass ratio of 3:1:6, and then added to pure water and stirred into a paste. The paste was then dried at 110°C for 12 hours, ground, pressed into tablets, and then calcined at 550°C for 5 hours to obtain a composition (Al2O3 mass percentage 75.0%, NiO mass percentage 6.2%, and SiO2 mass percentage 18.8%).

[0089] 1.3) The composition obtained in step 1.2) was slowly heated to 360°C for 5 hours under H2 atmosphere for reduction, and then silanized for 25 minutes under a SiH4 / H2 atmosphere with a volume ratio of 10%. It was then cooled to room temperature under H2 atmosphere to obtain the hydrogenation catalyst. The difference between this hydrogenation catalyst and that of Example 1 is that in step 1.2), Ni(NO3)2 aqueous solution was not added; instead, pure water was used, resulting in a hydrogenation catalyst containing excessively low levels of Ni and Ni-Si active components.

[0090] 2) De-olefin treatment:

[0091] 2.1) The hydrogenation catalyst is loaded into the hydrogenation reactor. Hydrogen gas is first introduced into the hydrogenation reactor to reduce the hydrogenation catalyst for pretreatment. The process conditions are: at a pressure of 1.0 MPa, the temperature is increased from room temperature to 400℃ at a heating rate of 2℃ / min, and the reduction pretreatment is carried out for 4 hours.

[0092] 2.2) The reforming product oil is transported from the reforming unit to the depentanizer. The process parameters of the depentanizer are: top pressure 0.95 MPa, top temperature 87℃, bottom temperature 215℃, tray temperature 160℃, and reflux ratio 0.2. After being processed by the depentanizer, the bottom oil of the depentanizer is transported to the hydrogenation reactor.

[0093] 2.3) Under hydrogen gas conditions, the material in the hydrogenation reactor is heated to carry out a hydrogenation catalytic reaction. The conditions for the hydrogenation catalytic reaction are: reaction temperature of 130℃, reaction pressure of 1.1MPa, volume hourly space velocity of 10h-1, and hydrogen-to-oil ratio of 23:1. After the reaction is completed, the deolefination treatment of the reformed oil is completed.

[0094] Comparative Example 3

[0095] 1) Preparation of hydrogenation catalyst:

[0096] 1.1) Nickel acetylacetone was dissolved in ethylene glycol at a mass ratio of 1:25 to obtain a modified nickel solution. Then, under stirring, silica powder was added to the modified nickel solution at a mass ratio of 1:26. While continuing to stir, a 10% sodium carbonate aqueous solution was slowly added until the pH value was 9.5. The resulting mixture was then heated to 120°C and reacted for 1.5 h. After the reaction was completed, the mixture was cooled, filtered, washed until neutral, and then the resulting solid was calcined at 400°C for 2.5 h and then ground to obtain NiO / SiO2 composite powder (NiO mass percentage was 25.1%).

[0097] 1.2) The dry adhesive powder of Al2O3 and the NiO / SiO2 composite powder prepared in step 1.1) were mixed evenly in a mass ratio of 3:1:6. Then, a Ni(NO3)2 aqueous solution with a concentration of 40wt% was added and stirred into a lake. The mixture was then dried at 110℃ for 12h, ground, pressed into tablets, and then calcined at 400℃ for 5h to obtain a composition (the mass percentage of Al2O3 is 60.3%, the mass percentage of NiO is 25.2%, and the mass percentage of SiO2 is 14.5%).

[0098] 1.3) The composition obtained in step 1.2) was slowly heated to 360°C for 5 hours under H2 atmosphere for reduction, and then silanized for 25 minutes under a SiH4 / H2 atmosphere with a volume ratio of 10%. It was then cooled to room temperature under H2 atmosphere to obtain the hydrogenation catalyst. The only difference between this hydrogenation catalyst and that of Example 1 is that the calcination temperature in steps 1.1) and 2) was too low.

[0099] 2) De-olefin treatment:

[0100] 2.1) The hydrogenation catalyst is loaded into the hydrogenation reactor. Hydrogen gas is first introduced into the hydrogenation reactor to reduce the hydrogenation catalyst for pretreatment. The process conditions are: at a pressure of 1.0 MPa, the temperature is increased from room temperature to 400℃ at a heating rate of 2℃ / min, and the reduction pretreatment is carried out for 4 hours.

[0101] 2.2) The reforming product oil is transported from the reforming unit to the depentanizer. The process parameters of the depentanizer are: top pressure 0.95 MPa, top temperature 87℃, bottom temperature 215℃, tray temperature 160℃, and reflux ratio 0.2. After being processed by the depentanizer, the bottom oil of the depentanizer is transported to the hydrogenation reactor.

[0102] 2.3) Under hydrogen gas conditions, the material in the hydrogenation reactor is heated to carry out a hydrogenation catalytic reaction. The conditions for the hydrogenation catalytic reaction are: reaction temperature 130℃, reaction pressure 1.1MPa, and volume hourly space velocity 10h⁻¹. -1 The hydrogen-to-oil ratio is 23:1, and the deolefinization treatment of the reformed oil is completed after the reaction.

[0103] Comparative Example 4

[0104] 1) Preparation of hydrogenation catalyst:

[0105] 1.1) Nickel acetylacetone was dissolved in ethylene glycol at a mass ratio of 1:25 to obtain a modified nickel solution. Then, under stirring, silica powder was added to the modified nickel solution at a mass ratio of 1:26. While continuing to stir, a 10% sodium carbonate aqueous solution was slowly added until the pH value was 9.5. The resulting mixture was then heated to 120°C and reacted for 1.5 h. After the reaction was completed, the mixture was cooled, filtered, washed until neutral, and then the resulting solid was calcined at 900°C for 2.5 h and then ground to obtain NiO / SiO2 composite powder (NiO mass percentage was 25.3%).

[0106] 1.2) Al2O3 dry adhesive powder and NiO / SiO2 composite powder prepared in step 1.1) were mixed evenly in a mass ratio of 3:1:6. Then, a Ni(NO3)2 aqueous solution with a concentration of 40wt% was added and stirred into a lake. The mixture was then dried at 110℃ for 12h, ground, pressed into tablets, and then calcined at 900℃ for 5h to obtain a composition (Al2O3 mass percentage 60.2%, NiO mass percentage 25.2%, SiO2 mass percentage 14.6%).

[0107] 1.3) The composition obtained in step 1.2) was slowly heated to 360°C for 5 hours under H2 atmosphere for reduction, and then silanized for 25 minutes under a SiH4 / H2 atmosphere with a volume ratio of 10%. It was then cooled to room temperature under H2 atmosphere to obtain the hydrogenation catalyst. The only difference between this hydrogenation catalyst and that of Example 1 is that the calcination temperature in steps 1.1) and 1.2) was too high.

[0108] 2) De-olefin treatment:

[0109] 2.1) The hydrogenation catalyst is loaded into the hydrogenation reactor. Hydrogen gas is first introduced into the hydrogenation reactor to reduce the hydrogenation catalyst for pretreatment. The process conditions are: at a pressure of 1.0 MPa, the temperature is increased from room temperature to 400℃ at a heating rate of 2℃ / min, and the reduction pretreatment is carried out for 4 hours.

[0110] 2.2) The reforming product oil is transported from the reforming unit to the depentanizer. The process parameters of the depentanizer are: top pressure 0.95 MPa, top temperature 87℃, bottom temperature 215℃, tray temperature 160℃, and reflux ratio 0.2. After being processed by the depentanizer, the bottom oil of the depentanizer is transported to the hydrogenation reactor.

[0111] 2.3) Under hydrogen gas conditions, the material in the hydrogenation reactor is heated to carry out a hydrogenation catalytic reaction. The conditions for the hydrogenation catalytic reaction are: reaction temperature 130℃, reaction pressure 1.1MPa, and volume hourly space velocity 10h⁻¹. -1 The hydrogen-to-oil ratio is 23:1, and the deolefinization treatment of the reformed oil is completed after the reaction.

[0112] Performance testing

[0113] The pore structure parameters of the catalyst were analyzed using a Tristar 3020 adsorption analyzer from Micromertics, USA. The measurement conditions were: adsorption temperature 350℃, vacuum environment 0.95×10-6~0.12×10-5MPa, and adsorption time 12h.

[0114] The bromine index of the product after catalytic hydrogenation of reformed oil was determined according to the national standard GB / T1815-2019. The AK-BR-1A bromine value and bromine index analyzer of Dalian Aoke Analytical Instrument Co., Ltd. was used. The unit of the bromine index of the sample is 100gBr / mg.

[0115] First, an Agilent 7890A-PONA gas chromatograph (Agilent Technologies, Inc.) was used to determine the aromatics and other components of the reformed oil before and after catalytic hydrogenation. Then, the aromatics damage rate after catalytic hydrogenation of the reformed oil was calculated using a formula. Measurement conditions: PONA column diameter 50 mm, nitrogen as carrier gas, initial column oven temperature 30℃, temperature ramped to 150℃ at a rate of 5℃ / min, held at final temperature for 2 min, capillary column flow rate 2.5 mL / min, injection port split ratio 50:1. FID detector temperature 220℃, hydrogen flow rate 40 mL / min, air flow rate 380 mL / min, nitrogen as carrier gas in the gas path connected to the FID for hydrocarbon analysis, capillary column flow rate 3 mL / min, injection port split ratio 50:1. TCD detector temperature 150℃, helium as carrier gas in the gas path connected to the TCD for inorganic gas analysis, packed column flow rate 20 mL / min. The aromatic loss rate (X) is calculated as X = (1 - w1 / w2) × 100%, where w1 is the mass fraction of aromatics in the reformate before catalytic hydrogenation (%), and w2 is the mass fraction of aromatics in the reformate after catalytic hydrogenation (%).

[0116] Table 1

[0117]

[0118] Table 1 shows the properties of the pentane bottom oil after the reforming product oil from the reforming unit has been processed by the pentane removal tower process in the examples.

[0119] Table 2

[0120]

[0121] As shown in Table 2, the bromine index and aromatic loss rate of the reformed oil after catalytic hydrogenation treatment in Examples 1-3 are both low, indicating that the hydrogenation catalyst prepared in Examples 1-3 of this invention has a high hydrogenation effect on olefins, but not a significant effect on aromatics, indicating that it has a higher hydrogenation selectivity for olefins.

[0122] The hydrogenation catalyst prepared in Comparative Example 1 does not contain Ni-Si / SiO2 components. It only contains Ni and Ni-Si active components on the Al2O3 support, but there is no strong interaction between Ni-Si / SiO2. This greatly reduces the hydrogenation catalyst's ability to adsorb hydrogen and other substances, resulting in a higher bromine index and aromatic loss rate during the hydrogenation of reformed oil.

[0123] The hydrogenation catalyst prepared in Comparative Example 2 contained too low levels of Ni and Ni-Si active components, which failed to fully utilize the catalytic hydrogenation activity of metallic Ni, resulting in a high bromine index and aromatic loss rate during the hydrogenation of reformed oil.

[0124] The hydrogenation catalyst prepared in Comparative Example 3 had a low NiO loading intensity due to its low calcination temperature, and the pore structure parameters of the final catalyst varied greatly. During the hydrogenation of reformed oil, the catalyst had excessively high reactivity, resulting in a large loss rate of aromatics and poor reaction selectivity. The hydrogenation catalyst prepared in Comparative Example 4 had an excessively high calcination temperature, which caused NiO to easily sinter together and be difficult to reduce. The final catalyst had an uneven distribution of active components and a dense pore structure, resulting in low reactivity and a high bromine index during the hydrogenation of reformed oil.

[0125] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0126] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for deolefination of reforming oil, characterized in that... Includes the following steps: A) The hydrogenation catalyst is loaded into the hydrogenation reactor, and hydrogen is passed into the hydrogenation reactor to perform reduction pretreatment on the hydrogenation catalyst; The preparation method of the hydrogenation catalyst is as follows: 1) Disperse SiO2 powder uniformly in an ethylene glycol solution of nickel acetylacetonate, adjust the system to be alkaline, heat the reaction, separate the reaction products and calcine to obtain NiO / SiO2 composite powder. 2) Mix NiO / SiO2 composite powder with alumina powder, add Ni(NO3)2 aqueous solution to the resulting mixture and stir until it becomes a paste, then calcine to obtain alumina loaded with NiO and NiO / SiO2; 3) The product from step 2) is first reduced by heating to 350-380℃ in a hydrogen atmosphere for 4-6 hours, then silanized in a SiH4 / H2 atmosphere with a SiH4 volume ratio of 5-15% for 20-30 minutes, and finally cooled to room temperature in a hydrogen atmosphere. The resulting hydrogenation catalyst uses alumina as a support and single-crystal Ni particles, Ni-Si, and Ni-Si / SiO2 supported on the support as active components. Ni-Si and Ni-Si / SiO2 are distributed between the single-crystal Ni particles. B) The reforming product oil is transported from the reforming unit to the depentanizer. After processing in the depentanizer, the bottom oil of the depentanizer is transported to the hydrotreating reactor. C) Under hydrogen gas conditions, the material in the hydrogenation reactor is heated, and after hydrogenation catalytic reaction, the deolefinization treatment of the reformed oil is completed.

2. The method for deolefination of reformed oil according to claim 1, characterized in that, In step A), the conditions for the reduction pretreatment are: under a pressure of 0.8-1.2 MPa, the temperature is increased from room temperature to 400℃ at a heating rate of 1.5-2.5℃ / min, and the reduction pretreatment lasts for 3-5 hours.

3. The method for deolefination of reformed oil according to claim 1, characterized in that, In step B), the process conditions for the depentane tower are: top pressure 0.93-0.98 MPa, top temperature 85-90℃, bottom temperature 210-220℃, tray temperature 140-180℃, and reflux ratio 0.2-0.

3.

4. The method for deolefination of reformed oil according to claim 1, characterized in that, In step C), the conditions for the hydrogenation catalytic reaction are: a reaction temperature of 120-140℃, a reaction pressure of 1.0-1.2 MPa, and a volume hourly space velocity of 8-12 h⁻¹. -1 The hydrogen-to-oil ratio is 21-25:

1.

5. The method for deolefination of reformed oil according to claim 1, characterized in that, In step A), the specific surface area of ​​the hydrogenation catalyst is 150-260 m². 2 / g, pore volume 0.3-0.7cm³ 3 / g, of which pores with a diameter of 5-10nm account for 60-80% of the total pore volume of the catalyst.

6. The method for deolefination of reformed oil according to claim 1, characterized in that, In step 1), the NiO content in the NiO / SiO2 composite powder is 20-30 wt%.

7. The method for deolefination of reformed oil according to claim 1 or 6, characterized in that: In step 1), the mass ratio of ethylene glycol to nickel acetylacetonate in the ethylene glycol solution is 20-30:

1.

8. The method for deolefination of reformed oil according to claim 1, characterized in that, In step 2), the content of Al2O3 in the alumina loaded with NiO and NiO / SiO2 is 60-70wt%, the content of NiO is 20-30wt%, and the content of SiO2 is 10-20wt%.

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